Once he gets neutered the spraying should stop. Probably not immediately, but shortly after. Also I know they can be difficult to get your hands on, but a crate would be REALLY useful.
I'd also advise not using soda cans with coins. Even though alot of people use that "technique", and it seems to work, really all you're doing is teaching the dog to be afraid of a coke can. I once heard a story about some people who put coins in a Diet Coke can, and after that the dog would reliably cower and run away when ever it saw a Diet Coke can (not any other kind.. just diet coke) However, I would take Formula's advise about the leash. If he's going to be in the house, un-crated, he needs to be with you so you can keep an eye on him, that way you can work pro actively and prevent the spraying before he does it.
Also, when you look for products to clean up with, try and find something more organic. Some of the products out there now contain chemicals you wouldn't want around your daughter/yourself/dog. With our 6 puppies inside, it gets pretty stinky. We found this stuff called Orange Oil. It's natural & Biodegradable and the only ingredient is orange peel extract and emulsifier. and it works better than everything else. So if you could find something like that it's worth the money. As for sprays that make dogs not want to mark, honestly, I think they are all rip offs.
this is what I have Orange Oil Concentrate Qt - Medina Ag Products
it's kind of expensive, but worth every penny, you can use it to clean, counter tops, floors, kills ant beds.. it has a million different safe and organic uses.
Oh, and my old boss used to use it in her dog training facility.. If you've ever been in one you know how much they can stink... people would come in though and they say how nice it smelled.