You've posted in the CB 1.2.2 boards, please upgrade.
Onto your issue, there's only so much you can do with Joomla SEO. It will use the following structure site/menu-alias/task/user-id|username, example as follows.
www.example.com/profiles/userdetails/62
OR
www.example.com/profiles/userdetails/admin
Both are used depending on how the URL is structured. "profiles" is my menu links alias and can be changed to whatever you want. The following can ONLY be done with 3rd party SEO, which I don't recommend.
www.example.com/admin
In order to remove
index.php you'd need to configure .htaccess usage as your URLs aren't being re-written at the moment via PHP.