RFID Reader for Arduino

Greetings,
I am in need of some help. I am totally new to RFID readers etc and have certain requirements for my project:

I am using an Arduino Micro and need an RFID reader and RFID tag that will work at a 6-7 inch range.

I have an ID-20LA wired up and would like to find a tag that will work with it. I know the ID-20LA is EM4001 compatible and have read of people using EM4200 tags and it working. from what i understand the EM4200 tag needs to be coded in a 64-bit architecture (some are 128-bit). Has anyone found this to work? And if so what tag did you use?

I am also considering trying a different RFID reader if necessary. Does anyone have suggestions on a possible alternative to the ID-20LA?

If you have any knowledge on this topic I would be most grateful.

Thanks,

Robin