[Plugin: AB Google Map Travel (AB-MAP)] How to use check box and radio on plugin options?

Hi,
I wish to make two more option fields, a check box (for enable/desamle something from plugin admin panel) and two radio boxes (to choose the distance in Miles/Kms) in my plugin “AB Google Map Travel“.

Please someone check the code here: http://plugins.svn.wordpress.org/ab-google-map-travel/trunk/ab-google-map-travel.php and advice me how to make them using options.

I think I must create them using add_option(). But how to check and save them in the admin panel?

Thanks,
Abooze