Luckily for you Frost is solid in both PvP and PvE and you won't really need to sacrifice much either way, you can make slight adjustments here and there as needed.
Be aware that PvP while leveling is messy. You will get ganked. Fights won't be fair. In most cases one talent point here and there is not going to make much of a difference aside from the core 1 pointer frost cooldowns.
First, I suggest you watch this:
Then, you can make some PvP-centric modifications to his build recommendations depending on our preference, such as:
- Forego maxing out Winter's Chill in favor of Imp. Cone of Cold to improve burst damage
- Forego maxing out Piercing Ice in favor of talents like Permafrost to improve kiting ability
The most noteworthy talents are:
- Ice Block, Ice Barrier, Cold Snap are phenomenal gank preventative abilities, so you'll always take them as soon as they're available on the way down the tree.
- The Frost Nova, Shatter & Ice Shards synergy will allow you to nuke a mofo. Frostbite talent is icing on that cake.
Oh, and if your focus is PvP, go engineering. Half of the shit Vurtne pulls in his videos is due to that.