Help Legal Real Estate Question?

Have a current lease with my landlord, which does not expire until April 30, 2008 and get subsidised housing istance, so the lease is also with the housing agency. Now all of a sudden the landlord wants me to sign another lease between he and I and charge me another $100.00 per month. without housing knowing, he said it would be a lease between he and I. I do NOT want to jeaporidise my housing istance. Please help? What are my legal rights and what should I do? Your help and advice is greatly apreciated.