The time frame you have to pay your mortgage before the bank puts your house into foreclosure due to missed mortgage payments depends on the bank and it should say exactly in your mortgage agreement papers as to how many mortgage payments you're allowed to miss before foreclosure.
Most banks will allow you to miss up to 3 mortgage payments before they start foreclosing on your mortgage and home however some banks will let you go 6 months of missing mortgage payments before sending your house into foreclosure.
If you're having trouble paying your mortgage you can and should speak with your bank about it so that they can work things out with you.
To get your house out of foreclosure you'll have to pay the full missed mortgage payments plus any late fees and possible other fees to bring your house out of foreclosure.
So try to keep the house from getting into foreclosure and if you know you cannot afford the mortgage payments anymore then you can and maybe should put your house up for sale and move into another cheaper home.
You'll have to use the sale proceeds to pay off the mortgage and maybe get a profit from it.