As others have indicated, teleporting with finesse just isn't canon. One could invoke the "Harry as unreliable narrator" argument, but the game setting and its rules - which do purport to reflect the DresdenVerse as it is and not just Dresden's impression of it - also establish that teleportation is incredibly hard. I would presume that skilled teleportation is even harder. That said, it is primarily hard because the RAW insist that you count each zone (and its zone border value, if any) as an increase on the difficulty. So long distance teleportation is MASSIVELY difficult.
Short range teleportation, however, seems within the bounds of reason. Even so, this seems like a really complicated example of it, more complicated than Evocation would allow. I wouldn't blame the GM for not allowing it at all, and I certainly wouldn't, not with Evocation. I'd allow it as a Thaumaturgical effect, something you can do a limited number of times per day, requiring preparation (so Thaumaturgy, or an Enchanted Item).
But, if your GM thinks it is fair game to do this as Evocation, then here is how I would do it (and these are appropriate Thaumaturgical routes as well).
The example of actual get-somewhere teleportation in the RAW was Harry's potion, which worked as an Enchanted Item (potion) providing a one-time Thaumaturgical substitute for an Athletics roll, working on the premise that the end effect was going to be movement: how hard should it be to move away from point A to point B with a normal Athletics roll? Or how far can you get with a particular Athletics score of 6 (for example)?
So in this case, the end effect is going to be... the person not hitting you with a bullet, right?
You could model that one of two ways, as I see it:
1) a simple Evocation Block, either a) protecting you, or b) on the opponent, Blocking the Guns skill (though he could overpower the Block and a little would get through)
2) an Evocation Maneuver, placing the equivalent of Disarmed (folks mentioned other good Aspects, too) on the opponent, which you would then Invoke to prevent them from attacking for a round or more, depending on your GM's narrative preference.