Take the bed pads others have suggested that you buy at the medical supply store, and fold them long ways several times and put inside her depends.
Take cwcowls suggestion of the 2 hr schedule, ask the Dr if they will check her for a UTI due to the frequency.
and also add a med for the incontience, { they now have a gel
you use once a day, instead of a pill}
no liquids after 5 or 6 pm except enough to take her bedtime meds with.
Does SHE TAKE A water pill? ie bumex or lasix? if so ask about the timing of it, they may be able to adjust the time of day its given.
dealing with it all the time. Hope this helps