Bad Gas

I just got a 1 to 2 year old pitbull sparkle her owner  was really bad to her didn't feed her properly she hadn't eaten for a week when I took her. She has horriable gas I wanted to know what to do to calm it down. She smells so bad she wakes herself and me up. Also I never owned a pitbull befor does anyone have tips like  she is either full of energy or sleeping is that normal. Thank you.