Are you just upgrading to specifically get the 4GB of RAM to recognise? Because if you are you don't need to. 32-Bit OS's (like the WinXP your probably using now) can't see all the 4GB of the RAM (due to the addressing limitations of 32Bit), so all you'd need to do to be able to utilise all of the 4GB would be to upgrade straight to a 64-bit OS, as the board supports 64-bit processors and OS's.
I got a asrock dual-vsta for under $70 and it has pci-express x16 slot and an agp. It is meant for overclocking and tweaking. it has a future slot which allows you to hook in a board and use am2 slot and ddr2 on the board. It is a sweet board.
I can sympathize, the A8R-POS is a flaky board. It took me a month of fiddling to get a stable overclock. I've come to the conclusion that the voltage regulation isn't tight enough. It's worst right at start up - preventing most overclocks from even booting. I ended up setting the memory and HT multipliers in the BIOS then using Clockgen to set the FSB. Surprisingly the board managed 320FSB - more than enough to get a 2.8GHz out of an Opti 165. All the same, I would have went with almost any of the 3200's if I'd known what a pain in the ass this board was going to be.