You should be entitled to around £22 per week working tax credit now.
If you applied for Housing Benefit now (ie. Local Housing Allowance) you would get the following allowances:
Couple over 18 £111.45
Couples' Earning disregard £10
Couple (as long as one of you over 25) working over 30 hours £17.10
This would give you a total allowance of £138.55 if one of you is 25yrs+ or £121.45 if neither of you is over 25yrs.
Your wage gives £250.34 per week
Your Working Tax Credits would be £22 per week.
That means your total income would be £272.34 per week. This assumes your partner does not get JSA.
Housing benefit is calculated by deducting your allowance from your income, to find your excess.
Using your maximum allowance of £138.55, your excess would be:
£272.34 - £138.55 = £133.79
65% of your excess is deducted from your Housing Benefit:
£133.79 x 0.65 = £86.96.
This is the amount that you would need to pay towards your rent.
You would be entitled to rent a 1 bedroom flat/house at the moment, then when the baby is born you will be entitled to rent a 2 bedroom flat/house.
You can look up the Local Housing Allowance Rate for your area. You must find a house/flat that costs equal to or less than that rate, or top-up the difference from your own income.
Once the baby is born, your Working Tax Credits will remain £22 and you will be able to get Child Tax Credit of approximately £65 per week.
The Child Tax Credits will reduce the amount of Housing benefit you get.