Creating a plugin that will change the default user registration

My site is avelim.co.il. The site is on Hebrew wordpress 3.5.1, using the theme Weaver 2.2.6 with many customization done by programmers. I need a plugin that does the following: 1. When you add a New user in the dashboard, Wordpress automatically creates a Nickname for that user. 2. The Nickname created is by default same as the Username 3. I want this changed. I want the plugin to do the following: a. In the add new user page the field "First Name" will be (required) too. b. The nickname created by default will be same as "First Name" There is a plugin in the depository that does something similar but I could not make it work. See [login to view URL] Freelancer can use that plugin as a base if he wants. Freelancer should allow 7 days for testing after he finishes his work, before getting paid. Work should be done in 24 hours after being awarded the project. I will install the plugin on a test site and when successful on live site.