hard to change gears and has no reverse

It could be a number of things, too many to list here. You will probably want to get it seen to by a mechanic. Check the transmission cable to make sure it doesn't need to be adjusted or if it's worn. Check the transmission control module. There really no quick fix for a problem like this. If you have the dealership or a mechanic run an engine diagnostic check it will tell you exactly what is wrong.

If you just bought it, immediatately take it back to the dealer or if its a private sale, take it to the owner. If the repairs cost over $500.00 in most states then the owner has to either pay for repairs or give you the purchase rprice back. If you have owned it since new, take it to the dealer to check for recalls. My opinion, Accents have tranny problems.