Your best bet is to buy a mix of snails, not just turbo. Different species of snails will eat different things, try a mix of trochus, turbo, astraea, and nassarius.
If you think it's okay to add another fish, a lawnmower blenny is a very hardy one that will wipe that algae out big time. I love mine! I know your tank just finished cycling, so you may want to wait a while and make sure your clowns make it okay before adding more fish, but a lawnmower blenny is definitely the best fish I've seen for knocking out algae.
As for starfish, the blue and orange ones (linkias) are extremely difficult to keep, even for the experienced. I would recommend either a bristle star or a serpent star -- I have one of each in my 55. They do a good job of keeping the bottom of the tank clean, and they will go after any food that your clowns leave behind! My starfish will chase down any food that bounces along the bottom.
If you are going to go with snails, I would not get any hermit crabs. I have a mix of both in my tank, and my hermits will sometimes kill the snails to get their shells :(.
Unfortunately the best way to deal with algae is to eliminate it by starving it of the nutrients it needs to survive (nitrates and phosphates). That's hard to do! I'm battling it right now. You can buy animals that will eat it, but it's better to not have it in the first place.
Good luck!