Do you have a price range?
Glock 22 (full size) 15 round capacity
Glock 23 (compact/medium size) 13 round capacity
Both are .40 cal S&W and ammo is typically in abundance.
There is a subcompact but that would be smaller than your specs. You can pick these up anywhere from $300 (used, usually police trade ins) to $500. New will typically be $500 to $600. The quality of these guns are only questioned by the ignorant.
Generally any of the full size or compact glocks chambered in .40 or .45.
Same goes for Springfield XD series and the Smith & Wesson semi-autos chambered in those rounds.
Ruger GP100 .357 magnum or .38 special (designed naturally to fire both as all .357 mag revolvers) so the Mrs. can choose to carry either type of ammunition, a mix, or whatever. Only 6 rounds though.... and it cost anywhere from $600 to $700.
If money is no issue and she wants a high capacity revolver:
Smith & Wesson 327PD, 8 round .357 and .38, typically found with a 4inch barrel although there is a 2 or 2.5in model as well. These guns are expensive in the $1000 range but they are lightweight in design and great and you may typically find them at dealers under $1000.
Also, consider the S&W Nightguard series in, .357/.38
If you really want her to have more than 6 rounds (or more than 8 in the case of the S&W 327PD) then you'll have to go with a semi-auto and I highly recommend Glock, Springfield, S&W.