If you're sure it was a 8800GT, then it will be PCI-E indeed.
I would suggest one of these for £25-35 delivered, which have 3 types of connectors: VGA, DVI & HDMI ports, & are also passively-cooled (fanless) so don't generate any noise:
HD 4350 click here / click here
HD 5450 click here / click here
If you prefer Amazon, then click here & click here
With HDMI you can also hook-up the latest LCD TVs/monitors that have this interface too. G