I would take her to a vet for some Revolution. Some dog shampoos contain pyrethrins that are toxic to cats, and vice versa. Heaven only know what they'd do to a guinea pig.
You can treat the carpet with diatomaceous earth (it's called DE, and you can get it at swimming pool supply places) or borax. BUT, be very careful.
Neither borax nor DE should ever be inhaled. Both are carcinogenic when inhaled, so get all people and pets out of the house while you're treating it, and wear a very good mask yourself.
The general procedure is to take a stiff broom and work the DE/borax into the carpet, a small area at a time (like a 2-foot square area). Work it in until it's no longer dusty when you walk on it, and leave it for several hours. When you come back vacuum everything, including the furniture, thoroughly a couple of times (keep the mask on while you're doing this), and carefully empty the vacuum bag outside. Dust everything thoroughly, and clean the pigs' cage.
What it does is dry the fleas and eggs out, so it's safe for treating the house, But it is NOT safe to put the powder directly on the pig or the dog.
If you do bathe the pig again, be sure the shampoo has no insecticides, especially pyrethrins, in it. Before you put the pig in the water, work a ring of shampoo around its neck, as close to the face as you can get without getting shampoo in its ears, eyes or mouth. This will keep the fleas from going to the head when you put the pig in the water.
Then get the rest of the pig wet, and work up a good lather with shampoo. Leave the shampoo on for about 10 minutes. Rinse the pig thoroughly, and pay special attention to getting the ring of shampoo around the neck off. Towel dry the pig, and then comb it thoroughly to get all the fleas off. Finish off the drying process with a hairdryer set on warm. I hope you don't have a texel!