Lillyfoxx is right, you need just 1000 points. If you look in your questlog in War Against the Hive you will see more details on your progress. However, I just wanted to add that it's important you do not confuse "war exp" for "favour left" war exp cannot be consumed or lost however favour left is how much war exp you have left to trade in to gain access to get the gooey masses past the hive gates. For the outfit they will go off of your war exp. This is what mine looks like and I do have the FULL Insectoid outfit:
Favour Left: 741
War Exp.: 1101
Done:
Antennae Blinding: 141
Hive Digestion: 135
Pore Stuffing: 142
Chitin Dissolving: 193
Guard Killing: 137
Crystal Destruction: 103