Evaporator replaced and water leaks on the floor

After an Automobile Technician replaced my evaporator on my Audi 90 Quattro, water leaks under the dashboard of the passenger's side and to the driver's side, the coldness dat enters the car is very small when compared to how it was cooling prior to the replacement. How do I stop this water from leaking under the dashboard and how can the coldness that enters the car be increased to normal.

Hint: I suspected that the Automobile Technician was not too sure when connecting the valve to the Evaporator as he interchanges the valve cap between the two valves with the other connector.

Thanks.
Frank