If you've already got a printer for the book, and a distribution plan, what else are you looking for?
Do you know how to format an e-book? It's a bit finicky, but not that difficult - I really like Guido Henkels' guide (http://guidohenkel.com/2010/12/take-pride-in-your-ebook-formatting/) but it gives you way more information than you need, really. You can also usually pay someone $50-75 to do the formatting for you.
Alternatively, some of the sites for uploading ebooks will do the formatting for you, as long as you put a reasonably clean version of the MS in at the start.
In terms of getting the book on Amazon? You can do that yourself, just create an account at kdp.amazon.com. If you want a print book sold at Amazon, I think you'll have to go through Createspace.
If you're looking for a way to hit other e-book retailers, be aware that this would disqualify you for the Kindle Select program, which may or may not be a big deal for you - worth looking into. But if you don't want to use Kindle Select, you can go to Smashwords and put your e-book up there, and they will distribute it to other e-retailers.
ETA: There's no secret button to push to "publish" your book. As soon as you have a copy available to the public, it's published. Good luck with it!