295420 Website - extension needed

I have designed a classified ads website and developed it in joomla. The page which displays the classified ads has an access level for registered users only. What I want to do is to add users manually with a certain username and password. The reason I want to do this is because I would like to have a profit from the visitors of the ads page. And the way I will use for that is sms. I am coopearting with a telecommunications company that will give me a list of usernames and passwords that those only should work with the site. So when somebody tries to open the ads page the website should explain him what to do to get a username and password using sms. I want somebody to do the following: 1. To make an extension that will let me add the users manually with a username and password that I will choose without joomla asking for an email. The user's email is not needed at all in my case. 2. I sould be able to set a time limit for all usernames and passwords to be active, but only after their first [login to view URL] is because when somebody gets the sms with the username and password those should be active for 24 hours only. 3. I have enabled the user's menu module. In my case I would like the page wchich now displays the user's details to show a clock with the remaining time of his username and password to be active. Experience with joomla and php is needed. The project should be finished in 4 days maximum. I am using joomla 1.5 in legacy 1.0.