Y:M:D & H:M:S Remaining B/T 2 Dates W/ Times

I am trying to create a "daily donut" to track how long it has been since I left for my current deployment, and how much time I have left until I return home. I would like to show exactly how many year(s), month(s), day(s), hour(s), minute(s), and second(s) (like 1 year, 4 months, 4 hours, 5 minutes, & 34 seconds not 1.0 year, 0.33 months, etc.) it has been (again, not 3600 seconds, 60 minutes, 1 hour, etc.), and how many I have left. I have spent many hours trying to figure this out, and I have even tried looking through this forum, but I still can't completely figure this out. I was close in figuring out the date differences in the x amount of years, months, and days format, but it wouldn't account for the time. I.E., 06/03/09 05:00:00 AM - 06/01/08 06:00:00 AM, would show 2 days, instead of 1 day (I'm not sure how to incorporate the time yet).

The variables are:
A1 Date I Left For My Deployment in M/DD/YY HH:MM:SS AM/PM
A2 =Now() Function in Same Date & Time Format as A1
A3 = Date I Get Home from My Deployment in Same Date & Time Format as A1

Any ideas or help? And if possible, I would like to be able to do this using excel's built in functions (not excel add-ons, vb, etc.), so that it would work on government computers.