If you don't want another dog for your own sake, then don't get another dog.
Stepping up training is a good idea. If you can find doggie playmates in your area, set up play dates.
Even snow can be a beneficial thing. A really simple game is burying treats in the snow and letting your dog dig them out. You can make this more complicated later by putting the treats in containers and then burying the entire container, scattering them across a wider range of snowfield, etc. A lot of people have remarked that asking their dogs to use their noses is very tiring to the dog, and that's one super easy way to do it.
ARCHMX TDCH Pongu the Insane, CD-C, RE, RL1X6, RL2X5, RL3X2 (GSD mix, b. Apr 2010)
Crookytail the Tigerwuff, RL1, ITD (Akita mix, b. Jan 2011)