Don't forget the cleaning of all the areas the dog gets into. And if you must, and have the ability to, you can flea bomb your house. I had to do that a few times. It's a pain to do, but well worth it. Make sure you get the one labeled for fleas too. Adams is a good cheap brand for shampooing and for home cleaning.
If you read the directions, the topical flea stuff works for up to 3 months against fleas and 1 month against ticks. I only ever used it every 3 months as the fleas can build up a resistance to the stuff. You also might find that each one works differently. Advantix worked best for my dog, and frontline seemed to do nothing.
When we adopted her from the pound she was covered in fleas and ticks, even the size of my thumbs. It looked sooo painful. They said the dipped her before adoption, but I found that hard to believe. So it took a long time before we were rid of them all, because we could only do so much that first night. Of course, once one falls down, you can be doomed.
My vet sold the frontline and advantix individually for 15$ a tube. No appointment needed, I just told the lady at the desk and she would ring me up for it. It was a little more expensive than buy the 3 or 6 pack, but more affordable to buy it when I needed it.