I see this is languishing but I fear it is a bit of a big question. Maybe that scared people off?
I was also a dedicated road bike kind of gal when I decided to try mountain biking (because my DH did and we watched a race that looked like fun). I had ridden DH's bike up the street and hated it because it was a low end bouncy dual suspension bike and it felt like riding a bouncy tractor after my nice efficient roadie!
Of course, having tried it on a bike of my own I am now hopelessly addicted and own two MTBs.
I would suggest a hardtail to start with because for a road rider who is used to a certain amount of efficiency in their bike, a hardtail doesn't feel quite so much like every pedal stroke is one inch forward and six bounces up and down!Also, there is a feeling that you will develop better technique riding a hardtail first. Plus on a bang for buck scale, you will usually be able to buy better gear in a hardtail.
I guess you can go two ways here....
You can buy a very low end hard tail to try and see if you like it. The up side to this is that you can usually get into a hardtail pretty cheaply. The running gear will not be a good as a better one (rear derallieur and fork are probably the items with most care factor) and it will be heavy, but if you decide you don't like it, then it wasn't too big a waste of money. I would try to get disc brakes if at all possible to stretch to it, since they are one of the wonders of the world!
Alternately, you buy a hardtail of a reasonable but not outrageously expensive standard. Perhaps one that is a bit lighter, has a Deore XT/SRAM X7 rear derallieur, a half decent fork, twin piston hydraulic disc brakes, perhaps women's specific depending on your body makeup? The down side of this is that you will probably stump up a reasonable amount of money for this kind of bike (not sure how much over your way) but the up side is that you will give yourself a fighting chance of enjoying riding MTB!
I chose the latter path (bought a Kona Lisa HT) and have a few friends who did the same (Giant Alias W, Avanti Barracuda) and all still have and enjoy the bikes. I also have a friend who did the former alternative and she also enjoyed it immensely but will consider an upgrade at some stage in her future.
The footnote is that after a year I went and bought a dual suspension bike once I had developed some skills (I have since lost them - just don't know where I put them) and worked out what I liked.
Hope that has been some help. If you have any more specific questions, please feel free to narrow it down.