How can I keep a dogs kennel warm outside in winter? read plz 10 points.?

I am a 14 year old girl. I have a 3 year old english springer spaniel, whose fur grows long, but usually we take her to the groomer to get it cut short so its easier... But now my mum babysits this little girl for 1 day a month. The girl and the dog dont get on at all lol (long story!!) so now my mum has banned the dog from the house while the girl is here!! (mum doesnt like the dog really) So, even in december (in england) the dog has to be outside most of the day, for 1 day a month and theres nothing i can do about it! We have a large fenced in garden. She has a dog house, and i am going to but a heating pad for it. I am planning to stuff the dog house with loooads of blankets, heat pad, get her to lay down, and tuck her in lol. But i doubt she'll stay like that! She loves being outside, but I am afraid shes gonna get tooo cold! I am going to buy her a doggy coat, in the winter her fur will be grown out long, and she will have food/water. I can also sit with her in loads of blankets in out garden shed which is really cozy lol. But i dont know what to doo. She is gonna have to be outside for 1 day a month, no matter what, she is completely banned from the house for 1 day a month!! Any other suggestions on what i can do with her? Should I put her in the garden shed with loads of blankets, and a kind of electric heater, or let her be in the yard, with access to her kennell full of blankets and stuff??