amember install and integration to current site ''look & feel''

Need Amember expert (or other membership software if you think something else is better) to install and seamlessly integrate all functionality into my existing site at www.paulsontraining.com. Will have members area with training videos, and various access levels, automatic expiration's, trials, etc. Mostly standard membership site stuff. But the look of the site can't change from the current site to suddenly Amember templates. All needs to look as yopu at above url. RightStart