Here are some free agents that I would like to see us go after.
The main free agent in my mind is Juan Pierre. He could give us great defense in center, he gets on base and steals bases. He had a somewhat bad year in Chicago, but when he is on he sets everything up for the homerun guys. But here is some under the radar guys to watch out for:

SP Kip Wells
RP Steve Cline
RP JC Romero
SP Randy Wolf
2B Jose Valentin

This list would not cost all that much and would sure up every hole we have except closer. Maybe we trade for one or sign either Gagne or Weathers, but we could use this list.