Replying to New camera questions.

I've been using a Nikon D40 for shooting biking, and I've decided I want to get more into it for skiing as well. I want to make videos as well, so I was thinking about a DSLR with video capability. My dad is into photography as well (he just bought a D300s) and he told me he'd buy me a cheap DSLR (such as a D5000) since the D40 is my sisters. My question here is should I go with the D5000, which does both pictures and videos, or get a cheap video camera and keep using the D40. I've had some problems with the D40 biking though. The AF doesn't work for shit, and the picture quality is pretty sketchy even with nice glass, which is why I was thinking the D5000. BUT, I've heard filming skiing with DSLRs is a bitch. Help?