Just bought New Vegas for PC and was hoping I could somehow get the DLC's from my xbox when I play on steam. Not going to buy them again....but having 'em would be nice. Can I actually do it/how?

Nope, different platform, hence you'll have to rebuy them if you want them.

Buying on one platform doesn't give you them on another.

Oh well, I'll be fine without. Thanks.

Just wait for next months 'Ultimate Edition'.

Or the next sale on Steam where you can get them dirt cheap.