I'm not sure what your question is - are you asking about pregnancy after IUD removal, or about when your most fertile time is?
It can take a few months for the uterus to adjust to not having an object inside and for periods to start regularly. But it can take any woman a while to get pregnant regardless of having had an IUD - there's no guarantee that a woman will get pregnant in her first month of trying?
Usually a woman's most fertile time is about 14 days after the date her period started. So if your period started on the 15th, count 14 days, which is 29. However, that depends on whether a woman's cycle is 28 days long. Many women vary a bit.
Don't try to take a test every month - that's expensive and stressful. I would just keep track of your periods for a few months so you know what's normal for you. Then you and your husband can plan better. If you need more help in calculating your most fertile time, talk to your doctor or borrow a couple of books from the public library - there are many useful guides and your librarian will be able to help you if you can't find what you are looking for. I know that a lot of people don't use the library - they just surf the internet. But sometimes having a book to refer to is helpful, and there's so much on the internet that is overwhelming or inaccurate, it's often harder to do it that way.