G5 PPC iMac Upgrade

Hi.My 3 year-old trouble free 20" G5 PPC 2GHz iMac with 240G HD & 1G memory has OS Tiger 10.4.11 with Micosoft Office for Mac, also Virtual PC, WinXP bundled with Photoshop Elements & WinXP version of ABBYY Finereader OCR software are installed in it. Its performance in running Windows is terribly very very slow. I am thinking of increasing the memory to its Max 2G and If anyone who has or knows a similar G5 2GHz iMac with 2G Memory installed in it, I would appreciate to know what is his/her experience regarding its performance in running Windows programs (Virtual PC & others) & also any post-installation problems encountered.

I would also like to know whether anyone knows or has modified the iMac screen display so it can also become a display for another Apple computer (Macbook & Mac Mini).

Thanks alot to all for your sharing in this Discussion Forum.
Michael.

My iMac Details:
iMac Model=PowerMac8,2 with CPU=PowerPC G5 (3.0) & CPU Speed=2 GHz / PPC 2GHz.
Hard Disk 233.76 GB / Memory=1G (512 MB DDR SDRAM X 2pcs with Speed=PC3200U-30330).