Of course when she later temporarily lost the use of her legs and had to spend 3 weeks in rehab, we had a serious problem. I constructed a temporary ramp out of old second-hand murder mysteries (thank goodness we are avid readers!) with roofing tiles laid over them. I wish I had taken a picture! It was pretty solid, but definitely temporary. Even the handyman had to admire it. Thank goodness he was able to put together an excellent one in an afternoon. Ours is wood which is no problem since it is inside the garage, and it is made specifically to our requirements: it is quite wide so that my mother doesn't fall off while trying to get around the dogs and it is a VERY gentle slope so that she doesn't balk at using it on her own. She feels much more independent with it: she can go sit outside to watch the dogs in the yard (she is afraid they will somehow get out the gate). Fortunately my mother does not have the wandering problems associated with Alzheimer's.
While I had not been able to find an appropriate ramp in the stores near us, I subsequently found that they are readily available on the Web. My favorite Allegro Medical Supply has quite a nice choice of ramps according to your personal needs and at good prices.
We were able to have one made reasonably ($100) by a handyman whom we had already had dealt with. If you don't know a handyman though, I can suggest that you contact your local Alzheimer's Association. They will most certainly be able to refer you to a "senior assistance and referral network" which will guarantee that the people you are put in contact with are "Elder Friendly" businesses. This is particularly reassuring when you come from out of state and don't know how or where to start.