Roommate Moved Out Still Hasn't Paid

[workthat]

My question involves landlord-tenant law in the State of: Florida

My roommate moved out the middle of August and still has not paid 2 utility bills for July. On top of that we are requiring her to pay half a month's rent. She still has not paid and I do not believe she will.
I will be taking this to court within the week, but I want to know what I should charge in regards to interest.
Any other tips?

[Mr. Knowitall]

Don't anticipate being awarded pre-judgment interest.