Outsourcing Small Business Accounting - Who Do I Talk To?

Outsourcing Small Business Accounting - Who Do I Talk To?
I'm a small business owner getting things off the ground and don't have time to play accountant all day to get the records straight. As a one-man operation at the moment, I'd like to find an accounting firm or accountant to whom I can simply give access to the bank account and have them handle all invoicing/accounts receivable, and then when I make a deposit, just let them know, and they'll see it on the online bank statement. I'd also like them to be able to track past-due payments and add interest appropriately. The point is to NOT have to send them paperwork, but to be able to pick up the phone and say, "hey invoice client X for 2500 bucks, payable 30 days, 4.5% interest for late payments". What kind of accountant do I need to find or talk to? A CPA, an accounting firm, what? And what do these guys typically charge?