If the car itself is in pretty decent shape I would put in a low mileage used motor. It'll be cheaper then going in and doing pistons, head etc. Plus usually you can get a warranty on the used motors. There's some on this website for around 2 grand. Alternatively If you just decide to patch it and resell I'd check www.rockauto for replacement parts.I figure an 06 with under 100k could probably be sold for 3500-4500 so in my opinion I it would be worth fixing.