I squirmed in my chair upon reading your question. On one hand, you gotta get to work or you cannot afford to fix it. I threw stop leak in my old Volvo to get by for a couple more years. I found some product partially blocking water ports in the head when I finally tore it down, but it did not cause any problem, and that high mileage Volvo engine was not worth much anyway. On the other hand, I have seen some bad stuff happen in MB water jackets that had been abused or neglected, and a Benz engine with 130k is still worth some money.
Where is the leak? If it is degrading plastic around the upper radiator hose, it will continue to degrade and Bar's Leak won't stop it. Similarly, if it is the O-ring seal between the aluminum core and the plastic end caps that is leaking due to being attacked by the wrong anti-freeze, then Bar's Leak probably won't help that either because of the movement as the aluminum expands and contracts more than the plastic.