There is always doggy diapers for the night time accidents.
my elderly (12 when it began, now 14 1/2) female shepherd mix (lab, greyhound, etc.) developed arthritis in her hips, which reduced her rectal continence. as this progressed, her stools became softer and her anal gland began to fill (the hard stools tend to press it clear). the fullness of the gland made her incontinence even worse, triggering a sense that she needed to move her bowels more frequently.
i live under the poverty line, but i have been able to help kaya (and myself!) get these problems somewhat under control. treating her arthritis with lower-cost drugs such as regular doses of glucosamine/condroitin (a $27 bottle has lasted six months) and several brief, gentle walks daily has helped reduce her pain and increase her strength. i give her half a tylenol on cold, wet days when her old bones ache! a good soft bed is important. plenty of fiber in the food is vital. i spend about $20 more monthly on a prescription diet designed to add fiber and firm up the stools. i also add pumpkin as kaya relishes it (and occasionally dust her food with a crushed liver treat to give her something to really enjoy).
if your dog's incontinence is urinary, i have heard that this is quite common in older female dogs. (i'm waiting for that one to hit!) a friend who rescues greyhounds says that her vet prescribes a quite inexpensive treatment for the problem. i believe she said that a bottle costing around $20 lasts a month, though of course your vet would be the person to ask. and, of course, there are diapers if the problem is strictly urinary.
everyone has her own tolerance level when it comes to a pet's inability to control its functions. what i finally decided was that i would rather have the poop AND the dog than get rid of the smelly, inconvenient, tiring mess and say goodbye to kaya as well. however, i am all too well acquainted with how difficult it is to get up every single night, clean up a mess (and sometimes the dog too), and walk the old one downstairs so she can pee as well--wind, snow, rain.
the main thing is that you will find your way to a solution that is right for you. when you do, trust it and don't take to heart any of the **** people are bound to give you--because they will, no matter which way you jump! there are no absolutes in this sort of thing. just know that there are lots of choices.
Have you taken her to the vet? It may be something simple such as a urinary tract infection which can be treated by antibiotics, or, if it is urinary incontinence, the urinary incontinence may respond to one of several prescription medications.
Even if it is something more serious such as bladder cancer, kidney disease, or diabetes, there are treatments that may be curative, or, if not curative, could at least extend lifespan with modalities such as surgery, holistic therapies, or Western medicine.