How do you unlock the UFO gun in toy story 3 after you blow up the dam for xbox 360

So, I know this must frustrate every one as much as it did me lol. But after you blow up the dam, go and buy the race car ( im not sure if it matters which one) and buy the race stunt track. After that get in the car, and do woodys ring collecting race quest thing. after that you should FINALLY unlock the ray gun for sure. So to recap, Buy the race car, the race track, and then beat the racing quest in the town. then u can unlock the UFO gun, and a carriage will bring it to you.