Yesterday, I called the company to ask some more questions about the new car shelter, and finalized the purchase. We are going for the more expensive option.
I believe we took the right decision for the long-term. Princess simply cannot scrape her car in the morning without risking injuring herself (she's had problems with tendons in her elbows). I cannot stand to spend money on something that will not last, and risks damaging our house.
We are using a 12 payments, no interest, financing. The expense is split 60/40 between me and Princess, like we do for all the structural expenses related to the house (our co-ownership is set up using the same ratio).