David,
Get her a
Gripmaster and encourage her to use it.
Be very very very
VERY wary of lightening springs on a defense guns. The reason guns come from the factory with springs of a particular weight is because most guns function most reliably with springs of the particular weight chosen by the gun's designers.
It was perhaps foolish to purchase a gun for your girlfriend without
her trying it on and seeing if it would work
for her, but I know that's crazy talk.
Even more crazy talk might be to suggest that perhaps in this particular case, she'd have been better served with a semi-automatic, which inherently has less aggressive recoil than a revolver of similar weight, and which is somewhat easier for people with weak fingers to shoot accurately. (Read what famous revolversmith Grant Cunningham has to say about choosing a revolver for a "non-dedicated shooter"
here.)
But that's all water under the bridge, now. Get her a Gripmaster and encourage her to build up her hand strength. Bonus: it'll make opening pickle jars easier!
Also -- teach her how to safely lower the hammer without firing, since it's a sure bet that at some point she's going to cock it to SA to save her finger strength. When she does, she'll also need to know how to safely avoid firing after cocking the gun.
pax,
Kathy