Good Capture Cards for games feeding off RCA cables

[CatalystiCam]

Hey guys, I'm looking for some tips to better my video quality on youtube.

Right now, I have a Diamond VC500 capture card that can record 240p to 480p. It has a number of different settings, only a few of which work well. Recording-wise, it can record in MP4, DVD, AVI, and that's just listing the ones that work right. There is other ones like MPEG-1 that don't work on this computer at least.

Recording with the DVD option has yielded the best quality for me, outputting in 480p, however it has some frame skips now and then which I think are just my computer. AVI is flat out unusable right now with my current computer, but I'm guessing it's the best bet when I have my new computer? The current option I use is m4 which outputs in 240 or 360p. Not good enough.

First of all, can I continue to use my current capture card on my new computer, and yield better results, or should I get a new one.

Considering I'm playing games that use RCA cables, and not HDMI ever, do I need HD? It's not going to look any better if the console itself is outputting in 480p, right?

These are some things I need to know. Do I need a new capture card? I'm hoping my diamond will suffice for now. I'm not playing any hd games.

Thanks guys.