Your card is considerably older than the 8800GT, and wouldn't be considered near equivalent.
However, I'm inclined to believe you would still be able to play with that one. For several months back during the LoL beta, I was using a card pretty much equivalent to what you have (if not slightly worse). I put all graphics settings to their lowest settings, and would get 15-20 fps. Not great, but playable if you aren't super picky.
I ended up upgrading my card to a newer budget card. I got an nVidia GT220. I've been able to play on high settings with no shadows and stay around 40 fps or so, sometimes going all the way up to 60. A vast improvement over what I had before, but it's by no means a high-end card still. But it's about all my machine can handle as far as power requirements and all.
@gruftwerk: They made both an AGP and PCI-E version of the 6200 LE