What your looking for is a template which you did describ, not a CMS. CMS is Joomla, phpNuke, ect. (CMS is Content Management System). As far as I know there isn't a all in one package but I could be wrong there.
WHMCS is one of the best billing/support software that I've encountered myself.
+1 for WHMCS as well - www.whmcs.com. It has everything you're looking for besides the hosting pages for your website unless you want to use their shopping cart template and integrate your website (which I wouldn't recommend). It has a very clean interface and easy to setup/use. Some of the other available billing systems that might interest you are clientexec.com, parallels.com for plesk billing, blesta.com, logicbill.com.
I looked over WHMCS and the price is such that i cant afford. I got this reseller from an offer and i didn't even expected that i will start a hosting business. so i prefer starting with a free script, is there any such one ? please advice thanks
If you need any futher help, just ask. I don't visit often here due to being very busy but tend to help when I am around. PHP Coin should be very easy to setup via cpanel's Fantastico. Setting up will take just a bit longer since a user/database has to be setup.