How to Increase Screen Resolution in Linux Mint. (Parallels and iMac)

I'm very new to Linux and I've decided to install Linux Mint on a Virtual Machine on my iMac 27 inch using Parallels 7. But, the screen resolution is stuck at 800x600 and there are no options in the setting that will let me change it to a higher setting. How can I increase the resolution of Linux Mint? Is there a way to do it through the terminal? I tried downloading the drivers for my raideon 6970m but it's not helping at all. I also tried installing Parallels Tools, but that did not help with the screen resolution. Also tried setting my memory settings for the VM to 512mb... still didn't work at all.