Their CSS is rather complicated. I haven't tried this but if you copy the section of template.css that is marked as module variations to the bottom of your current template.css it should add all the extension variations. You'll have to change conflicting names, or comment out the current module variations if there are conflicts.
There could be problems if your current template has some of the same class names. In any event, all the styling for the modules is there. Like I said, I haven't tried it. Don't do this on your live site. Make a copy first, and try it there. Be sure you have a backup.
/* Module Variations */
.box1 .rt-block, .box2 .rt-block, .box3 .rt-block, .box4 .rt-block, .box5 .rt-block, .box6 .rt-block, .box7 .rt-block, .box8 .rt-block, .box9 .rt-block, .box10 .rt-block, .noticebox1 .rt-block, .noticebox2 .rt-block, .noticebox3 .rt-block, .noticebox4 .rt-block {border-radius: 5px;}
#rt-header-surround .box5 .rt-block, #rt-footer-surround .box5 .rt-block {border: 0;}
.module-icon {width: 18px;height: 18px;position: absolute;top: -3px;right: -3px;}
.icon1 .module-icon, .icon11 .module-icon {background-position: 0 0;}
.icon2 .module-icon, .icon12 .module-icon {background-position: -22px 0;}
.icon3 .module-icon, .icon13 .module-icon {background-position: 0 -22px;}
.icon4 .module-icon, .icon14 .module-icon {background-position: -22px -22px;}
.icon5 .module-icon {background-position: 0 -44px;}
.icon6 .module-icon {background-position: -22px -44px;}
.icon7 .module-icon {background-position: 0 -66px;}
.icon8 .module-icon {background-position: -22px -66px;}
.icon9 .module-icon {background-position: 0 -88px;}
.icon10 .module-icon {background-position: -22px -88px;}
.title1 .rt-block, .title2 .rt-block, .title3 .rt-block, .title4 .rt-block {position: relative;padding-bottom: 35px;margin-bottom: 15px;}
.title1 .module-title-surround, .title3 .module-title-surround {position: absolute;bottom: -6px;right: 0;height: 29px;}
.title2 .module-title-surround, .title4 .module-title-surround {position: absolute;bottom: -6px;left: 10px;height: 29px;}
.title1 .module-title, .title2 .module-title, .title3 .module-title, .title4 .module-title {height: 29px;margin-left: 10px;}
.title1 .module-title .title, .title2 .module-title .title, .title3 .module-title .title, .title4 .module-title .title {height: 24px;margin-left: -10px;padding: 5px 10px 0 15px;font-size: 130%;line-height: 130%;}
.font-size-is-large .title1 .module-title .title, .font-size-is-large .title2 .module-title .title, .font-size-is-large .title3 .module-title .title, .font-size-is-large .title4 .module-title .title, .font-size-is-xlarge .title1 .module-title .title, .font-size-is-xlarge .title2 .module-title .title, .font-size-is-xlarge .title3 .module-title .title, .font-size-is-xlarge .title4 .module-title .title {line-height: 100%;}
.title5 .module-title {padding-bottom: 10px;margin-bottom: 5px;}
.noticebox1 a, .noticebox2 a, .noticebox3 a, .noticebox4 a {color: inherit;}
.noticebox1 .module-icon {background-position: -22px -22px;}
.noticebox2 .module-icon {background-position: 0 -22px;}
.noticebox3 .module-icon {background-position: -22px 0;}
.noticebox4 .module-icon {background-position: 0 0;}
/* Module Standard Variations */
.promo .module-title .title {font-size: 190%;}
.promo .module-content p {font-size: 140%;line-height: 140%;margin-bottom: 0;}
.standardcase .module-title .title {text-transform: inherit;}
.lowercase .module-title .title {text-transform: lowercase;}
.uppercase .module-title .title {text-transform: uppercase;}
.flush .rt-block {padding: 0;}
.flushtop .rt-block {padding-top: 0;}
.flushbottom .rt-block {padding-bottom: 0;}
#rt-popup, #rt-popuplogin {display: none;}