Trash the rib and sell the other pieces.
OR
what we did was take the end of the crib (we had solid 'camel back' ends) and made it into a little headboard for our girls. You just use the crib mattress, the crib springy thing that the mattress is currently sitting on and have 4 little supports made for each corner of the 'springy thing'. Our guy used 2X4 to make an 'L' for each corner. Attach the 'head board' to the feet and you're good to go.
We have a twin dust ruffle that you fold in about 1/2 length wise to cover the legs and you get to use the same mattress, same crib sheets, we just use a blanket as a 'comforter' . My kids are 4 and one of them is pretty tall and she still fits nicely on her little bed.