Best agp card is a 3850 agp while there was a very limited run of 3870 for the agp but very rare almost nonexistent to be honest. Then there is the overpriced 4650/70 and almost all are ddr2 which suck.
basically what i wanna do is buy like a 23 inch HDMI tv and play dota and watch movies on that using a HDMI cord from the tv to my comp but i dont have a HDMI output so i need one from a graphics card that will go smooth with the computer
What type of ram is your system using? DDR1 or DDR2? If ddr2 then just buy a new or second hand 775 board that has pcie and just change everything onto the new board. Might have to reinstall windows but that isn't to much trouble then pick up a cheap 6450. That will give you hdmi and something that can handle all the new codecs.
Just take a look at the ram and look at what shape the chips are. DDR1 has rectangular chips that you can clearly see the pins while DDR2 and above are square shaped BGA that you don't easily see the pins beneath the chips.