So sorry to hear of this, its never a good time of year and money is becoming an issue for so many people.
White steam on starting is not necessarily a cause for concern, especially in this weather as condensation builds up and evaporates as the engine runs, usually lasts a few minutes and goes. If it were still there after or during a long drive, then there is an area of concern.
If the water levels are not dropping, probably a none issue.
Without a drive or at least private parking, insurance will be a problem, sadly not much you can do there and will be an issue regardless of the car type. One thing a friend of mine looked at was literally car sharing, he and his friend having joint ownership and the car was kept on the friends drive. Bills were split and it did help a lot, but that was for a lotus elan which was also used for show.
The irony I so have the same issue, though not with the TF, which has be every good and pretty cheap for me to run up to now, but with the family workhorse, the Citroen c5. It's going to need work doing but fundamentally the car is sound and has never let us down, but because of insurance and my F being written off (not my fault) it will be over £850 this year, despite having another years no claims on that policy.
I you have exhausted all other options and don't want to break the car, the only other option may be to sell, but as me tend above, breaking could well get you more money in the long run.