sheesh...what a messy thread.
You need to remove the 60FPS limit in CS:S via the console. Like someone else said...Google for the command.
Even if you are SURE you installed it right...do it again. Wipe your system clear of ALL video drivers. I mean get them back to Windows defaults 640*480 or w/e it is...then reinstall them. This should get rid of any kind of driver conflicts you MIGHT have.
Your 6800U is an awesome card...its merely the users (or your) job to figure out what is wrong with his/her computer to get it up to speed with the new hardware. Some cards are just plug and play...i've had a few i just popped in and installed drivers for and they worked great. OTHER cards require a more precise approach...they want ENTIRE solitude on your system before they will really shine (alot of ATi cards are this way, and i guess now you have found an nVidia one that is this way too.)
nVidia and ATi both make solid cards...but as expected not 100% of them are going to work properly. It could very well be that you got a bad card and nothing you do fixes its crappy performance. Return/RMA/Sell/Trade it for a new one that works and then move on. If you ditch nVidia over this one card...just remember you might pop in a brand new X800XL just to find out it also is defective and you have to RMA it. It happens to everyone...the trick is to see if it's your fault, or the cards fault, and then diagnose the problem without exploding