||08-24-2011 12:26 PM
You'll be able to get a new ship each time you rank up, so your next ship will be when you reach Lieutenant Commander 1. There are 11 levels to each rank, though the last level is basically so that you apply enough of your remaining skill points to trigger the promotion. At that point, you'll receive a hail from Admiral Quinn at Earth Spacedock, recalling you in order to promote you. You'll get new Bridge Officer, inventory, bank, and ship slots when you rank up.
As far as ships on the C-Store go, some of them are available for use on lower tiers, some are only for use at the endgame tiers (Rear Admiral and Vice Admiral). The descriptions for the ships should make it clear what can be used when (for example, anything with "Refit" or "Retrofit" in its name is for endgame).
A great resource, in addition to these forums, is STO Wiki
, by the way.
Edited to add: Beaten to the punch! That's what I get for going long-winded. ;)