Defroster, middle vent problem

[HLK350]

Hey guys first time on this board....

4 days ago I went over this metal plate that was in the middle of the highway unfortunately I didn't have time to avoid it.
Tuesday my coolant started leaking pretty badly and the middle of my engine was smoking, also when I put on the defroster the passenger middle vent is blowing out air. I took it to a local garage and there were 2 hoses that needed changing for the leaking. He said for the air flowing through the middle vent when setting is at defrost that most likely it's got to do with my heater core which I replaced 2 years ago. When the defroster on the passenger side is on there is air hitting the windshield but it is not enough as most of it is flowing through the middle vent and my windows won't defog. Also smells coolant in the car. When the the defroster is turned off there is hardly any air coming out through the middle vent. The driver's side is perfect. BMW 2009 X5 4.8

Any suggestions would be appreciated.