Prestigio PAP 7500 rooting
Rooting is the easiest part, but it still may be impossible. Some of the methods I would try:


You can try to log in through ADB, see if you're already logged in as root.
You can also try universal root exploits, one of them may work.
Also you can try to obtain an original ROM for the device, root it on the PC and flash it on the device.


What is very hard (handfuls of experienced developers are spending months with each device) is porting custom ROMs (CM, Ubuntu Touch) to a previously unsupported device. Since you've found no existing recovery for it, let alone a ROM, you will have to do the porting yourself which will take a lot of time and if you aren't careful, you can easily brick your device.