There seem to be some unsympathetic responses here, so I’m going to stick up for AGH. Her rent includes a portion for the use of the garage. If the garage is taken out, then that portion of the rent should be refunded so that she can find alternative parking elsewhere.
I’m not convinced by the “everybody’s in the same boat” argument. Even though everyone is inconvenienced more or less equally, at the end of the day the lot owners will also own improved common property. The tenants will be exactly where they started.
You can’t expect tenants to pay for repairs and upgrades of common property, either directly or in kind, e.g. by having to rent parking in a nearby building.
My advice would be to try to find alternative parking near your home – maybe there’s a Facebook page for residents in your area – and ask your landlord to reduce the rent by the equivalent amount. And, yes, call your insurers and check that your insurance hasn’t been invalidated (which it might be if you don’t inform them).