Your renal consultant is right, you need to see the diabetic consultant!
There are several other drugs that deal with insulin resistance, but only the diabetic consultant will know which would be the more suitable one for you,
Acarbose, then you got the thiazolidinediones such as pioglitazone but I don't know enough about them to even hazard a guess whether there are any indicators that may rule them out with kidney problems... I know that they aren't used often due to possible issues with the liver, so need high degree of monitoring!
So best to ask to be referred to the diabetic consultant...