I need advice on a gokart engine problem?

I bought this 8hp gokart with offroad tires and lights from a guy for $350 a while back. Ive only ridden it a few times in my yard, and now it stopped starting so I took it apart and found a goldball size hole under the starter in the block. You can see the crankshaft and the connecting rod broken on the piston. Im trying to figure out if I should: try to sell it as is and make atleast some of my money back, or should I invest in buying another engine and then selling it. If I bought another engine, how much would it be and could I get one with alot of horsepower or is there a mimit to what a gokart can handle?