What is wrong with my Dove? Please help!!!?

My dove's beak is overgrown, she is very tired all the time, not alert anymore, and she can't walk or keep herself upright. I tried to lay her down on the floor and she flipped onto her back, she couldn't get back on her feet by herself, so I put on her on the floor again but she fell on her side right when her feet touched the floor. I can't afford to take her to the vet. She's 5 or 6 years old. Please tell me what's wrong with her and what I can do.