Precision M4800 need upgrade for WWAN and Data Encryption card

At this moment I live and work in Ukraine.
In this country I cant find any official DELL representative.
So I decided to ask here.
Two weeks ago I've purchased used (but in very good condition) Precision M4800.
And now I have 2 questions about upgrade of my laptop.
1. Can anyone give me a list of supported WWAN modules? Real experience is appreciated! I know about Sierra MC7355, but I think $250 is too much for official and original but outdated WWAN module.

2. I've discovered that my laptop support hardware data encryption. Can I purchase Dell Data Encryption Accelerator Card to enable this option in my laptop? I need hardware encryption / decryption.
Any advice will be appreciated.
Thank you!