Should I use onboard video or purchase a pci video card?

I just bought a 1080p monitor and movies and video clips are very choppy at max resolution. I have a dell e310 with Intel GMA 900 Graphics with 128MB Shared Memory. I have a PCIe 1x slot but i can't find many video cards to fit and none are within my budget. Will a 50 - 60 dollar pci video card be an improvement or should i stick with the onboard?