My understanding is that the Imperial Remnant is fully consolidated into the First Order.
Following the events in the film, its anyone's guess as to whether or not the Republic remains. General Hux seemed confidant that the Starkiller would "Bring and end to their senate and their cherished fleet".
C3P0 later mentions that "without the Republic fleet, we're doomed". It *seems* the Republic has been decapitated.
The Senate is gone. But wonderful part of a Democracy is that you can elect a new leadership ASAP and begin war preparations immediately.
By destroying the Senate, the First Order murdered citizens of _Every_ world in the Republic. And by blowing up several planets, they committed an atrocity that made the Empire's treatment of Aldaraan look restrained.
So. The Starkiller base was a strategic blunder on par with what the Japanese made at Perl Harbor. And like at Perl Harbor, we can expect the Fleet to be rebuilt in 2 weeks.
Well. Unless the Republic is so fractured and fragile that it is not able to withstand a leadership transition.