Hello Shirlthegirl, yes, I see you want what we would all love to have and don't because of the problems and cost.
No expert here, but just some of my own thoughts and experience. You could heat and light your greenhouse and grow things in there all year, but I doubt if the results would justify the cost. Lighting is quite a complex business to get good results and good units are very expensive. Here's a link to a site which will give you technical information about lighting and let you see the prices of the units.
Greenhouse lighting
It would also be very expensive to heat your greenhouse all winter. There's been quite a lot on the forum recently about Parafin heaters. Some people are happy with them and some are not. I had one which I hated. I didn't find it satisfactory in any way. But yes, it is a big advantage if you can put some heat in the greenhouse.I now have an electric fan heater which I find just the job. I only use it for a few weeks a year. I start my seeds indoors and put them in the greenhouse once they have reached the size where it's no longer viable to have all that stuff in the house. Or for things I've got outside in May, but the threat of a frosty night. I think the cost is reasonable but I don't know how much. Piglet worked out what it cost him to heat his greenhouse to 10 degrees for about 8 weeks. I think it was about £85 but you might be able to find that thread, or ask him. And he does grow a lot of stuff. I'm sure some of our more expert greenhouse growers will be along with more detailed info.
Keep us posted on what you decide to go for.