converting to YPbPr

I've got an ancient HDTV with only YPbPr available, and I want to get video from my PC to it. problem is, neither of the graphics cards on my PC have a dongle for such a purpose.

I have an integrated Radeon HD 3300 which I think might be my best bet: if I buy one of those simple VGA->RGB cables will catalyst allow me to switch it to YPbPr? i've seen some discussion in various places as to this, but its always referring to old Radeon 9800s or the like.

I also have an asus 9800GT with VGA, DVI, and HDMI outputs (no funky dongle output). Is there any way to cheaply convert any of these to YPbPr on an nVidia card through the nvidia drivers and a simple VGA or DVI -> RGB cable?

I'm not interested in spending $50-150 on a converter box, I'm looking for a driver/software based solution that can allow me to use one of those $5 VGA-> RGB or DVI->RGB cables on monoprice. thanks for your help!

suggestions are decent, but not exactly what i'm looking for. maybe I should be clearer:

Is there anyone who can confirm (or deny) that the ATI VGA adapter here will work with the integrated ATI Radeon 3300 card on my motherboard?

I know cards with HDTV out are available cheap if you keep your eyes open, but I don't want to replace my mid-range graphics card with a low-end alternative just for HDTV.