Invite.php coding-giving users x amount of invites

Would like to give users a set number of invites and if they use them all, i’d like to give them more.
okay my question to you guys is that I got this already in the widget

href="javascript:workforchange('p2','changer2','Invite','Invite');" id='changer2'>Invite</a>
<span id='p2' style='display:none'>

<br />Invites left: 1<br /><form action="invite.php" method="post"><table border=0><tr><td>Username: </td><td><input type="text" size="13" name="username" /></td></tr><tr><td>Password: </td><td><input type="text" name="pass"  size="13"/></td></tr><tr><td>E-Mail: </td><td><input type="text" name="email"  size="13"/></td></tr></table><input type="submit" value="Invite!" /><input type="hidden" name="loginname" value="jordybear82" type="hidden" /><input type="hidden" name="userid" value="" type="hidden" /></form><br /></span>
<br />

any who reads this throw this into your widget as text and you can see
that a link will appear, and you click on it, and it opens up with

Invites left: 1
Username:
Password:
E-Mail:

now, i was thinking could I use or, can someone whip up a code invite.php

from this guys php files
http://wordpress.org/extend/plugins/invite-friends/
if, we or anyone can boom, now there’s an actual widget, but from this guy i was told that he had to go into his database, and install, or write the code for the invite.php in his msql or something, I don’t know, Im not a coding expert. so any help would be AWSOME

thanks
Dave