I'm afraid i'm with the majority and would run with the gas central heating. I would suggest not turning off the rads in the other rooms as you'd need to keep the rest of the house aired to stop things going damp - ie your clothes, bedding, etc. If you've got heat in one room and none at all in the remainder of the house the rest of the house will feel much colder and the heating would need to work harder to keep that one room warm.
If keeping the house warm on a limited budget is priority - have you got loft insulation? There are a few organisations around that will install it for free if you're on a limited budget or are claiming. Also, I'm sure I read something about cavity wall insulation being offered free too, although I can't remember where I read it. Perhaps a token, card or budget meter (not sure of their proper name) where you pay as you go so to speak may be an option.
Hope that helps.