After I glaced over your hitters, I was expecting to see a weak pitching staff, but I could not find one.
This is the type of team that I would stand pat with. You do not have any holes!
In fact, you have so many good young arms that you may even be able to spare a one of two of them to get your SS upgrade.
Look for potentially huge seasons from Kip Wells, Adam Eaton and Jeff Weaver. Although it is unlikely that all three of them give you great numbers, at least one of them should make you happy with your investment.
Also, you may want to look to add a reliever to your bench. Perhaps a possible 2-1 trade could give you room to add a free agent.
. This is a solid team