You sound very motivated and I have no doubt you will shed this weight, but it will take some time. A crash diet is not a good idea. But you knew that. :)
The easiest time to shed pregnancy pounds is right after you give birth and while you are still nursing. I gather you are not nursing anymore. (But if you have another baby... )
You almost certainly gained a pound because you are gaining muscle, which is normal when you start exercising. That's good, because the more muscle you have, the higher your metabolism and the more fuel (food) you'll burn. Don't worry about that pound; you probably have more muscle and less fat already.
Keep exercising, be patient, and pay attention to what you are eating. You might keep a journal for four days--being very honest--to find out what you are eating and drinking. You might be surprised because people often are eating more food or more sweets than they think.
Your diet should be a diet high in fiber,
especially soluble fiber, as well as a medium level of fat (like 25% to 30% of calories). As much fruit as you want because the fiber will fill you up. Also nuts, vegetables, roots (beets, carrots, potatos), fish, lean meat, and eggs are all good.
Consider going on the "Paleolithic diet," in which you eat as little as possible of the following:
1. Dairy,
2. all Cereals and grains (rice, wheat, corn, barley, bread, and pasta) and
3. Added Oils and fat (butter, margerine, and cooking oils).
Don't drink juice or sodas; stick to water if you are thirsty. The fruit and vegetables are full of water, too.
Here are some good sources of soluble fiber.
Soluble Fiber Tipsheet
If you really feel like you can't give up cereal completely, have oatmeal for breakfast and otherwise avoid grain products.
Here's another good fiber site:
Dietary fiber: An essential part of a healthy diet - MayoClinic.com
If this is really far from what you normally eat, make small changes at first.
Good luck!