does the gts 450 1gb work on my pc? since i could buy it now and upgrade my pc later, so the card wont be a total awste on my new system. So will it work on my pc?
you didn't mention a gts 450 before...
gts 450 is now two generations old. while it might provide decent performance for your current pc (i think your cpu will bottleneck the gts 450), it might not be a good card compared to what is available today at gts 450's price level (newegg @ $113-140 for gddr5 version). i found a his radeon hd 6790 going for $125.
the gts 450 requires a 6 pin pcie power connector. if your psu is too old, it might not be able to support the gts 450.
when you upgrade your pc later, you might have to upgrade your gts 450 to keep up with the current gaming cards' performance.