250 gts vs hd 5450

Not at all. Your GTS 250 is many times faster than an HD5450.

your current gts250 is the better card, if you have a second PCI-E slot you could SLI that GTS250..

it seems alot of cards are slower than my card thats under 200, I look at the galaxy cards like the 500 series and the 300 series, they just have more memory and dx11

300 series?
Your card is roughly on par with the HD5750/6750(same card), HD4850 and the GTS 450. These cards tend to cost around $100-120.
If you want a significant upgrade I would be looking at cards like the GTX 460 and the HD6850 for $150-170.