Upgrade my Processor?

I have a 20' iMac core duo. I love the monitor, but the processor is a little old. I haven't seen any info on using it in the monitor mode (say with a mac mini). Can this be done? If not, can the processor be upgraded to work with OS X Lion? About how much would it cost to do that? Thanks



Unfortunately, the only way to upgrade the processor is to get a newer Mac.