Welcome to the forum.
There's a lot of members who have been in the same position, and will be happy to help you.
As a first step to your understanding on the Visa application process you should review this thread How to apply for a Fiance Visa
Take special note of the financial requirements for self-employed.
The other issue that you'll need to sort out is getting a British passport for your child.
If you do a quick search you'll find some good info.
Again, quite a few members here have experience of that and will be able to guide you.
