You got it right there freaky. Uninstall your old drivers in add/remove programes or goto your divice manager, shut down your computer, and swtich off at mains, remove your computer case, and locate your old graphics card, un-screw it from its slot, and swap it, and install your drivers for it and your away!
Open the the side of the case (remember to unplug first and use antistatic wrist band) there will be a small clip at the end of the AGP slot pull it back, pull out the card and push the new one in it's place untill the clip moves back in. put the case back on plug your moniter back in to the new card and switch back on it will work with the same drivers but if you want run the disc that came with it.
The Mesh case has a spring loaded clip that holds all PCI/AGP cards in place. You just release the clip, then all the cards are easily removed. Very tidy and saves fiddling with screws 10:10 for Mesh !!