For like $25 a day you really cannot beat this. Be prepared to move the benches out yourself and clean the space yourself too. The city doesn't have the manpower to respond to custom requests, although they mean well.
You can rent a power washer and cleaning equipment at the Ace Hardware across from Wal-mart. You can also rent chairs from there to fill the space. We were able to comfortably seat about 75 people with two rows and a 5 foot aisle down the middle, and fit a four piece orchestra in the back, complete with floral arrangements.
Click on each tool to see a sample.