Sorry the first little one didn't work out for you.What is your BP set-up like?
I would recommend buying from someone who really knows BPs to avoid getting snakes that are sick. I bought all 8 of mine from reputable breeders and have had zero problems with any of them.
Seven months seems a little old to be that low of a weight... I would look for a seven month old that was more like 500-700g.