Your husbands cashflow looks to be fine.
There really isn't any actual amount stated in the 'immigration rules' that indicate just how much disposable income is considered as 'sufficient'.
But just as a guide you would need about £106 per week disposable income (after rent etc) per couple, with around £62 additional per child (up to 20yrs)
From what you've said you'll be fine.
Nearly everyone on here who has taken the IELTS test has been able to pass.
There are quite a few postings here on just that if you search around.
Take care
