THat is a shitty choice of resolutions (480i/576i).
A scaler that does all of those choices (s videos/composite/dvi/component) will not be cheap.
www.svideo.com
Here's one option, but it only converts HDMI to composite and svideo. If you get that plus a box that converts HDMI/DVI (it's the same thing, just different plugs) to Component (YPbPr) then you'd be set. I got one from AudioAuthority and I've been thrilled with it.