Need help understanding codes

[memy26]

Ok here's the deal. We are wanting to book a trip for December 19-27th, 2009

My question is can I book it now and possibly get a better deal later if I come across a code?

Also if I book now can I go back and add the ME later as its too early to book airfare?

Thanks for any help

 

[mbanks21]

Yes and yes