For the stability ball, it depends how tall you are. I believe up to 5'7", it's a 55cm ball. After that it's 65 cm. As far as the band, it's a 6 ft. medium tension resistance band. You can get them either at collagevideo.com or fwonline.com. There are also other sites which I can't remember at the moment but I'm sure others will chime in.
Marcy