I am a ninety year old vet and I am the only care giver for my wife who is not ambulatory. Can I get some help(home service) from the VA?

There is a program for caregivers. Check with the social worker at your VA either by phone or in person depending how far. A social worker can then come into your home and see how much care is needed. There is also financial help available in resolutions made in the last year.

Contact Your VA Help Center...
Just Call Your Medical Hospital And Ask For Assistance
The VA Can Be Of Assistance, But Her Medicare Program Can Help As Well.
If You Hit A Dead End, As Often Happens, Then Contact The DVA
And Then Watch The Action....

The VA Caregiver programs are mainly focused on caregivers taking care of you (as the vet), but there may be programs available from the VA for your situation if you meet some other eligibility depending on your situation (for example, "housebound pensions" if you are mostly unable to leave your home) and your ability to care for your wife right now.

As Maj Kim Patterson said, a VA Social Worker can help with the VA programs.

Additionally, I HIGHLY recommend that your State's Veteran Affairs office (search on your state and add Veteran Affairs to the search term) as there is likely other programs in your state that you can access in addition to what the VA offers. They should be very familiar with both the State and Federal programs that can assist you.

My last comment is that you should be looking at doing what a lot of individuals DON'T do and that is considering what can be done "if I'm not here". Make sure you keep this foremost in your discussions with the individuals at your state's veterans office so they don't just focus on you and your needs 'right now' but also get processes in place in case you aren't around.