No one can say for sure, but having said that the current trend doesn't seem to suggest that scores will come down below the 440-450 mark.
My brother's been in queue with 411 points for, i think,2 years (his profile expired 6 months ago after which he didn't bother again)
I'd say you need about 40 points more.
You didn't give points break down but in general to increase points:
1. IELTS Score - increasing it may substantially increases your points in Section C (100 points total) and also for the IELTS score itself
2. Learn French(?)
3. Complete a masters degree if you don't have one.
I think you should check how your IELTS score is affecting the points in section C (which gives a total of 100 points which can substantially come down because of IELTS score).
If let's say you scored 50/100 in section C because of low IELTS score, a good score will boost your points up by 50, plus whatever more you get for the IELTS score itself!