Need help to buy 05 Dodge Stratus parts?

I have an 05 Dodge Stratus sedan with the 2.4L interference engine. The A/C recently started acting up. First the air only blew out of the defrost vents. It still blows cold air and heat but only through the defrost vents. Yesterday, water started leaking from inside the penger side of the car. I took it to a shop today and they said that my heater core and blend door are out. They made a by-p so that the fluid wont continue to leak inside the car. I was wondering where I can find the heater core and blend door so that I can attempt the job myself. I know that it's a PITA to fix since the whole dash has to be disembled, but it's going to cost around $1200. No auto parts store around has the parts, so any help would be appreciated. Thanks in advance.