there was someone on there selling whole kits with cyls pistons ect for about 500, but Id rather just get an entire motor for near the same price, keep what you want for spare parts and sell the rest off to make some money back. just get assurance that the compression is good in whatever you get.
As far as getting rid of the bike I dunno, there a million of em around here that sell for nothing, I dont know how it around you, but you could prob get another one later on and most likelly you`ll have more fun on the banshee.