There are a number of books like this:
http://www.amazon.co.uk/exec/obidos/ASIN/09106 27363
and quite a few articles and websites such as this
http://www.caterersearch.com/Articles/2006/07/ 06/308001/Opening+your+own+restaurant.htm
or this:
http://www.startups.co.uk/YSB2GxM.html
I think 3 out of 4 fail in year 1, so read up as much as you can and don't make optimistic projections - going in with a "it'll all work out" attitude is a great way to get real poor, real fast.
Look in a few restaurants in the area (hopefully there aren't that many!) go on a Tuesday evening, not a Friday - how many people are in there? What do you reckon the average bill will be?
Remember rent, staff costs, tax, VAT, heating and lighting, insurance food costs and wastage - how would you be left with? now how long will that take you to pay off your capital costs like kitchen equipment and furniture? Don't forget interest on that loan!
That's the sort of thinking you need to do before you start
Best of luck though