I dont own that house, But I have built several dura craft and have 4 kits waiting to be built. I have in the past gone on ebay and asked the people that are selling their dollhouses to measure missing parts. One woman even traced a difficult part for me. I even had one sell me a copy of directions when mine went missing. Builders are like that. Since I dont know what the parts are. this may help:
I get replacement milled wood from micromark.com http://www.micromark.com/SearchResult.aspxdeptIdFilter=0&searchPhrase=precision+milled+basswood+siding+for+hobbies+and+model+building the problem is how big a piece do you need. The catalog has more choices then the web site and its free.
But Without the measurements its hard. I have ended up purchasing the same dollhouse twice (the tower was missing parts). Not a big waste since messing up is my middle name lol and after a few dollhouses + furniture everything gets used sooner or later (you decide to add a room build a garage...or just make a canopy bed). But sometimes thats not feasible. So I piece the thing together with tape and figure out what is missing - measure the empty space and make a paper pattern. And purchase the wood. I use 1/8" plywood (mostly lowes) and I purchase from manchester or micro mark I hope this helps.