Sorry for the loss of the DL, but be glad bike commuting is a reward in itself.
Layer up to be cold for the first bit. Maybe look at adding a rack/pannier bags and fenders to that shiny new trek. Make sure it fits you well, although that's probably less important for your short commute.
I highly recommend thrift stores for bike clothes on the cheap. I picked up a rain/wind light jacket and a few tight fitting wool sweaters for a song, and they are working rather well. I use wool GI issue glove liners from the Army/Navy store inside my ski gloves. Not ideal but cheap and very warm.