दीवाने

Bistro means a small informal restaurant which serves wine. Buff means an ardent follower.

Bistro
From Wikipedia, the free encyclopedia

A bistro, or bistrot, is a familiar name for a type of small restaurant serving moderately priced simple meals in an unpretentious setting, especially in Paris, France. A bistro may not offer professional service or printed menus, and it will usually specialize in simple classic dishes such as steak au poivre, French onion soup, and coq au vin. The term is possibly derived from the Russian: бы́стро (pronounced [ˈbɨstrə]) which means 'quickly.' Russian soldiers occupying France after the Napoleonic Wars would frequently demand that French civilians serve their food quickly, shouting the word that evolved into the neologism 'bistro' at them.[1] In Russia restaurants were not traditionally called "bistro".
This etymology is disputed: the most common version is that Cossack soldiers that occupied Paris in 1815 screamed the word in restaurants. However, the first recorded use of the word appears in 1884,[2] almost seventy years later, and again in 1892 ("bistrot"). Nevertheless, many French scholars saw that version as a humiliating one and started looking for others. One precursor suggested for the word could be "bistraud", a word in the Poitou dialect which means a "lesser servant." Another offered is bistouille or bistrouille, a colloquial term from the northern area of France,[3] which is a mixture of brandy and coffee; precisely the kind of beverage that could be served at a bistro.
http://en.wikipedia.org/wiki/Bistro
From the above, I think 'bistro' in your context should be transliterated. As this term is used with a particular bistro having an English name (The Big Chill ), it would not be appropriate to use the term ढाबा. Otherwise, a bistro sounds to me like our ढाबा.

…..और फ़तेहपुरी का कुल्फ़ी-फ़ालूदा अब भी चटोरों को खींचते है पर आधे….
http://www.bbc.co.uk/hindi/regionalnews/story/2007/06/printa...
लेकिन मै बहुत चटोरा हूँ, दुनिया की हर डिश पर हाथ साफ़ करने के लिये एवरैडी रहता हूँ।
http://www.kalpana.it/hindi/blog/2005/11/blog-post_16.html

The word 'bistro' means a restaurant that also serves drinks like a pub or a bar, and the word 'food buff' means the food lovers. Hence, the translation of the text in question could be something like this.

बड़े-बूढ़े हों या नन्हे-मुन्ने बच्चे, बेतकल्लुफ़ी के माहौल वाला इतालवी रेस्तरां बिग चिल शहर भर के भोजन प्रेमियों को आकर्षित करता है.

Transliteration is better.

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Note added at 14 hrs (2007-12-31 16:33:54 GMT)
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Dear Mrudulaji,

Wish you a very happy new year. I highly appreciate your views but I never intended to hurt. If we follow certain rules then it everything becomes useful to all, i.e. I religiously follow using English full stop instead of Viram, because layout looks beautiful, many objects this but I convince them. In my views there are two things, a Language and a Translation. Language is always in search of getting rich in his vastness. Translations are to communicate. If the origin of term is not in native, then Dictionary and Kudoz platform does the same thing, and only those terms are discussed which a translator is unable to get through and if translator was aware what and where to use he may not have asked here. Nobody forces nor can force, but can insist regularly which may be felt as nagging but it may serve the purpose or may generate hatred. If you see my Kudoz, you may notice that I try to be Alamance, can slip somewhere. Everyone learns here, me and you and all of us will die learning but learning is endless. New one will join old will go. In Hindi more and more original terms are commonly adapted, spoken and known by the masses. But it took years to become popular. As an experienced person (In fact I too commit so many errors that only reviewer knows, for example you can see my English, at times it may be horrible, but once you see my qualifications and then compare my performance than you will give Kudoz point to me. If you wish to know my real field of work go to this link: "15 Dollar Refrigerator" : http://www.createthefuturecontest.com/pages/view/entriesdeta...
I take liberty to share my frank views, if you or anybody else is hurt, I tender my apologies to you and all those who are hurt. I wrote to share the reason of emphasis on transliteration, you may see, a day will come (I may not remain to see) when English will become a common Indian language!

Best regards, Arun