If something is in a sellers disclosure, is it non-negotiable?

I am looking at a property which has historic casement windows. In the sellers disclosure it discusses the missing/broken window panes. After the home inspection I requested that the windows be fixed/replaced, an outlet converted to GFCI and for the bathroom tub to be fixed and toilet unclogged. The seller will fix outlets in the living room but not the one I want converted to GFCI in the kitchen, the bathroom plumbing, but NOT the windows. Since they are historical that will be a costly fix and unrepaired that is a dealbreaker. My real estate agent stated she would pay out of pocket to fix my windows, but she was very rude and does not seem to have my interests in mind as she never told the seller that I was not interested unless the windows were fixed. Can I break my contract on the property and get my good faith deposit back? If not, can I get a new realtor to help me with the remainder of the contract?