i am going to UK for 2and a half weeks....how much money should i bring?

Well, keep in mind the exchange rate is horrible--you'll get between 45 and 50 pounds for 100 dollars. Things are generally a little more expensive in the UK than in the US, especially restaurants (which might not matter to you) and clothes or CDs (which you might). Depending on where you go, prices will vary--London is a LOT more expensive than the north, for example. If you can, just set some money aside in your bank account and then use your credit card. That way you won't have to bring cash or pay to exchange money.

The exchange rates may be rubbish so you'll need to bring some money. The cost of everything (depending where you go) is sky high. I'd suggest bring all you possibly can - just in case. Have a nice holiday.

Estimation - £1,000+