Where can I sell 4 pieces of art?

I have 4 pieces of art in my house and I was thinking of selling them all. One is a 3D serigraph by James Rizzi called "In the Heart of the City". The other 3 are original cartoon sells of 2 scenes from Garfield and 1 scene from Looney Toons. All 3 are signed by the cartoonists (i.e. Jim Davis and Friz Freleng) and sold for about $500 in both 1995 and 1989. And for the James Rizzi serigraph it would probably cost around $3500 when it was sold around 2001. Where would be a good place to find the prices now and a good place to sell them around the 45230 ZIP code. I would very much appreciate it if someone could help me in the selling of these pieces of art.