You could try McNett Tenacious Sealing and Repair tape I have fixed my awning with this stuff I do not know what it would be like on a roof light, but after 3 year the rip in the awning roof still holds.
cheap hot glue gun,did my Daughters,lasted a full season till she got a new one.
------------- Think this year is to follow old meet friends for 2014.
If you cant do someone a good turn,don`t do them a bad one,its nice to be nice you know,and little things mean much more later in life.
Pete.