Any Pills I Can Take to Gain Weight for Butt Augmentation?

I need butt augmentation,I can't do implants,I want fat transfer and I have little or no fats,I am 110 pounds max and 5"3 little or no butt and I want a nicki minaj size.what can I d to gain weight?i ave drank ensure,gnc shakes,I try to eat but my appetite is really lw,the past 3 months I have done nothing but try to eat and sleep.I need a quick 20 or 30pds any ideas or prescriptions or anything that can help?i can't do implants at all, need my but b4 dec 2012