Am I HD Enabled?

I have an DIRECTV HD-DVR receiver in my living room attached to my big screen VISIO Television (which is HD ready).  I am not very technically savvy on this subject.  I've been told that most HD-ready TV's still need a card (usually received from the provider) inserted in the TV to activate HD.  This was not done by the installer.  I've also been told that the dish itself is different for HD....it has at least two pickups, instead of just one.....my dish is a slimline-3 with only one pickup.  Is this an HD capable dish, or did the installer put the wrong one on my roof?  I am paying for HD every month, so would appreciate this being clarified.

Thank you.