Pic32 Memory question

Hi, I'm programming a pic32mx220f32D and have unfortunately run out of Kseg0 prog memory. In the manual it says that kseg0 and kseg1 RAM and PROGRAM sections are programmable. Firstly how could RAM be programmable and why would you have uncached RAM (Kseg1)? and if you have experience with how this is done could you assist?