Can I repo my car back from my friend?

I sold amy car to my friend in november for $3500. he put dwn $1500. with payments of $400 mth. .(Payoff date may 24'th) he has paid me $200. in jan.6'th and $220. in Jan 24'th then paid me $540.00 this month. He owes $1040. and he wrecked the car it is a mechanic shop on hold because he doesn't have the money to fix it and they won't work on it because i'm the lein holder. what do i need to do to repo my car (Texas). Can i just go get it? (the mechanic says i can if i want to). And my friend has no money and no job. what can i do i'm tired of the BS.