Used car has defects warranty?

Hello, I bought a used Fiat Stilo Kombi 1.8 16v BJ 2004 with 1 year used car warranty from a dealer at the end of April, unfortunately I found 2 faults in the one month since I drove it. 1. In the rear of the vehicle squeaking the brakes extremely loud (I would say metal), and even during the ride it sounds sometimes as if the car was braking even though the brake was not operated. 2. What I find much worse is that car leaks is, as soon as it starts to rain heavily, the sky in the trunk is completely wet so that water drips into the trunk, because in the sky there are different spots (only on the trunk) I assume that before the purchase there was something wrong with it. I didn’t notice the two defects during the short test drive, what possibilities do I have now at the dealer? Ps: I personally would not have bought this car with the water damage, when selling again I can certainly expect a very high depreciation because of the water damage you don’t know what everything has become wet technology etc. and which consequent damage results from it in a few years. Would look forward to an answer. Mfg Goldenretriever