Pregnant cat lost mucus plug 2 days ago when should labor start?

She has had booger like stuff coming out of her girl parts for two days now and she is so big that she can't clean herself so I have to do it for her I know that the kittens are ok because they are still moving quite alot but was just wondering how long before I should expect the kittens my husband will not let me take her to the vet due to our money situation and I'm kind of getting a little worried abou her. Also she has had no signs of contractions at all either.