Exchange 2013 Archiving/eDiscovery AND High Availablity/Disaster Recovery

OK, I am by no means any sort of Exchange Guru.  I have been the sole admin of the Exchange environment where I work; however, and we are in the process of starting an upgrade to our current Exchange environment.  Going from ONE Exch 2007 server on Win2K3 to two Exch 2013 servers on Windows 2012 servers.

My requirements are to get Messaging Policies and Compliance configured and set and better disaster recovery.

My thinking is this, get two servers.  Both would have CAS and Mailbox roles installed.  One would be physically set up in our main facility and another in our colocation center.  Then get these clustered together.

I have two questions regarding this:

1. Is it possible, or are there better ways (especially financially)?
2. Would I need to double the licensing, especially for CALs?

Thanks