Power Mac G5 question

I have a power Mac G5 late 2005 which I want to install a Radeon card so can have morphos as it doesn't support nivda cards What card would be compatible? Also when I boot the machine I want to be able to choose whether to start up morphos or Mac OS X tiger what boot program can I use?

Here is my Mac from a serial number search http://www.everymac.com/systems/apple/powermac_g5/specs/powermac_g5_dual_2.0.htm l