Default Acer Iconia A500 demo restore?

So I acqired an Acer Iconia A500 tablet, and I kinda want to restore the OS on it.
You see, the OS ended up being a demo version of Android 3.0.1, somehow without Andriod Market/ Google Play store.
Does anyone have any ideas? Do I need to root (please no GingerBreak, I already tried and failed)
I'm posting because the last time I tried to "fix" a tablet I bricked a Kindle Fire
So, what I would like to accomplish:
1) replace the OS with a new version of 3.0.1, or 3.1, or 3.2
or
2)replace the OS with a newer version of Andriod (4.4, 4.3, even 4.2)
but most importantly,
3) get the tab to have Google Play Store so I can download other apps.

I'm very much a noob when it comes to dev for this kind of thing.
And I need help, because I don't want to brick this one like I bricked my Kindle Fire (which also ended up being a demo device).
Thanks in advance!
-KillerKondor