I have to say, actually, probably NOT. You can try--you'll have to ramp up your feeding to every 5 days, at least. The male will be ready with no problem, but not that female who is only 600 grams. My guess is, she'll hit 1200, but there's a VERY low chance she'll make it to 1500.
Given that many young female balls go through a finicky winter between 800 and 1200 grams, you will most likely have to wait until the following year. From my experience, what they gained in the previous year is roughly what you can expect them to gain in the following year. Gaining 900 grams isn't out of the question in a year, but in only 6 months? It's pretty unlikely.