Hello,
The loss of her bladder and the difficulty standing is linked, it is likely due to arthritis but it could also be a sign of a mild stroke or something Neurological. The problem is at her age this is going to get worse and not better the average life span of a Lab is around 12-14 years and since she is a mix I would guesstimate it to 14-16 years.
Your vet will want to do a blood panel as well as a x ray. Depending on the results she may need to go see a Neurologist as I suspect this is neurological more then anything else. Of course there are tests that can be run to determine the cause and if treatment is a option but your going to need a specialist more then likely as this is out of your vets field of expertise.
For now you will need to keep her in the house, you can pick up dog diapers at your local pet store to help keep her dry and prevent infection from laying in her own urine. Massage will help on her hips and legs as well to help keep the blood flowing and to decreases pain and swelling. Heat wraps will help as well. Take a towel and heat it to a comfortable level in the dryer and then apply over her back hips and legs. Massing over this will help immensely.
You can give aspirin as long as there are no bleeding conditions present and as long as the dog is not on any naisads from the vet. Also if any corticosteroids in a oral or injectable form have been given you can not give aspirin.The dosage for aspirin is 5mgs per pound of body weight every 12 hours for a maximum of two days.
Make sure she gets enough fluids and continue to hand feed. I would suggest putting her on a bland diet of boiled chicken and rice as this is easier to digest.
Walter
Breeder
Breeder and pet health consultant. Have spent a number of years with dog rescue, training and health