My husband and I are separated but not divorced. I get spousal and child support but not enough for bills. Could I get more to fix up house to sell

Yes, you can do that.  You should file a motion with the court outlining the amount of the mortgage, what the costs are and that you want to sell.  You may not be able to sell the house until the divorce is final, or, if you can work something out, you might allow him to keep the house, but get additional support to find other housing.   This is something the courts can adjust if you cannot afford the house and don't want it.