php software add joomla web site

We have i website in joomla 3.1. we wnat to add a management content like [login to view URL] for online administration of our custumer we need to devlop a software in ou out of the joomla for administration of our custumer in money lender principali we need to do this ; 1 - click to start fill - weekly periodical payments 14 days or monthly 2 - Then I get 3, 6 or 12 installments 3 - I get the date of the first payment and the amount and all dates appear following this information back précédament . 4 - the amount of all dates is identical 5 - right amount of each payment a check box can be either postpone the payment of $ 25 fee or the payment not paid a $ 40 fee. also having an opportunity to influence key to its expense has zero or defer payments remains outstanding but no charge. when one of its two box automatically check the baths loan payments 1 extends an additional box appears as a result of payments following the previous frequency . 6 - the right of the screen the software must calculate the payments made ​​by the customer the total amount repaid at all times and it was still having to repay the costs . when a payment is not paid or defer the software must take into account is not pay check . 7 - at the end of all baths loan when the last payment date just spend the last such payments are the property Jan. 15 Jan. 16 , 24 hours after the last payment I received an alert saying here example its 50 clients with their code names and their customers last payment is then complete Mount dimension I'll go over each one was to see if the customer has an account balance has are such expense payments without provisions and deferred charges payments. Mount side then I want to add a box manually after the loan has to return the last customer payments that are able to cancel his costs and expenses such payments 2 and 4 in the balance of the customer falls to zero eventually I want the total , saying total payments made ​​by the customer $ 750.00 total repay zero 8 - to transfer all of my Excel book when customers are ready to finish see pdf files for the look or exemple.