Hi, from your post ,one thing that stands out.."I don't sing".
You may want to work on some songs that you can sing ...you don't have to be a great singer..with your PSR3000, the background arranging and vocal harmonizer will add to your performance..
When you play "non dancing" locations , such as nursing homes..vocals are pretty much a must...At dancing venues, you can get by without vocals..

Is your pricing in line with the other performers? Don't price yourself too high or too low[setting your price too low, may give the opinion that you are not worth the competition level..]

It may be better for you to use a booking agent that specializes in nursing homes..this may give you more bookings..
Good luck, Fran