The owner of the upstairs condo did nothing, so he is not liable. The tenant is the one who would be liable. Also, the HOA's insurance may cover you, since a neighbor caused the problem.
Why do you not have insurance to protect this important investment?
You need to submit a claim to the upstairs owner's insurance company, to your own insurance company, and to your hoa's insurance company. One or all of them should provide some coverage.