In reply to durkules:
Speak to Martin Moran about guiding tailored to suit the time constraints you can commit to.
http://www.moran-mountain.co.uk/moran-mountaineering/winter-courses.html
I fully recommend him as I'm sure other will on here.
If you want to play it 'safe' with the time you have available, Scotland will offer more reliable conditions, unless you strike it lucky and we get a nation-wide cold snap at the time you have booked.
Very broad-brush, late February holds the general consensus of being the most reliable date-wise. However being this warm and wet island this can prove very hit-and-miss.
Good luck with your future adventures, but be mindful that a low-cost alternative would be to get in touch with people on here. I'm sure you'll find people with spare axes and crampons etc (me included!), all you'd need is a stiff pair of mountaineering boots (B1/B2) - but you could always hire these and the appropriate clothing which no doubt you already own.