What's "1600x900p"? I hope that "P" is a typo and not something you imagined.
The CPU and the GPU are good enough together for some very high resolution gaming.
Although the PSU might just be cutting it too close, the max wattage of your GPU is about 292/300W under heavy load. If you add a few HDD's or DVD drives plus a few fans it's going to go pretty tough on the PSU. If possible go for a 500W 80+ PSU. That should be fine even if you were to ever go SLI on a new mobo.
And the Board (Mobo) it's intel, not something I'd choose if I wanted to upgrade my stuff a little later.