I'd drop a combat spell or two before dropping the gun. Nothing gets you focus fired faster than flinging napalm and sometimes it's just better to lay down suppressive fire or use a less obvious area debuff.
Bioware is bad because it hurts your casting for little actual benefit.
I agree with Whiskeyjack on the machine pistols skill - in places with lots of background count or circumstances where "geek the mage first" is in play, using a gun and not just relying your magical abilities is a huge plus - learning Increase Aim is something to consider for these situations as well. Reminds me of a quote from somewhere in the Shadowrun universe that read something like "A good mage knows how to blast something with magic. A better one knows when to use a SMG instead." (( should also note that my character will likely want to learn Shape Water as well at some point, because it fits her so well. Deflection is also one that's in consideration.)
At this point, I'm thinking I will focus on Centering and Focused Concentration as some of my first goals. I'm less sure of my foci choices - a Power Focus is an obvious good choice. Sustaining foci are good, but (without looking back at the rule book to be certain), I believe they were aspected to one of the five spell categories - I have a spell in each category worth sustaining, so that makes it a little difficult to choose which. (In particular, Combat Sense, Increase Reflexes, and Improved Invisibility are things that I would expect to be maintaining for long periods of time. Levitate and Mob Mind would be things that I might sustain sometimes, but not for long enough to consider drain a major issue.)
As long as we're talking Drain, how addictive is Psyche? It's the only one I considered before besides Long Haul as something she might use, but the difficulty of breaking the habit is something I'd be concerned about. (Simulated dice rolls on Addiction tests would be helpful to illustrate this.)
Someone also claimed that Lightning Bolt is as easy to dodge as a gun shot - I'd appreciate an illustration on this one, comparing rolls on a burst shot from my gun, Lightning Bolt, and Ball Lightning. If the difference is drastic enough I'd consider replacing Lightning with the limited version of Ball Lightning.
One other question that comes up is if the Concealment Spirit power is any good at concealing your astral signature from others with Astral Perception - I imagine the answer to that is no. In that case, Extended Masking looks very worthwhile. Would be good to know the answer on that subject.
I think Shielding, Spell Shaping, Invocation, and Channeling are still on the long term table - depending on how long she lives and such things. I'll have to discuss with the GM his likelihood to pop spells.