In terms of a bottle neck no as the 3000+ is more than enough for current games out there.
When newer games come out in the future that require high cpu imput then there may be an issue but the card is responsible for all the heavy work and will run like a dream in that setup.
When you can though maybe a getting a cpu that has an FSB 400MHZDDR and get some PC3200 400MHZDDR RAM would go very well with that monster card.
It's going to cost a few quid so I bet you have enough money for a new 3200+ AMD64 with 1MB L2 CACHE and some nice cosair twin gaming modules!!!!