Have you tried approaching your council, as there are grants available for insulation, new heating systems etc, with a new upper limit of I believe �3,500. We recently had our bungelow fitted with a new combi boiler, new radiators etc loft insulation and cavity wall insulation, we had to pay an excess of �400 on the system but the difference its made is amazing. You might not be elligable for a grant but if you don't ask you wont know and if you are you may be able to get the work you want done for free