I don't think the one suggested will fit into your telescope. From the looks of it you can only use 1.25" accessories in the focuser.
There are 2 that might do the job:
http://www.bintel.com.au/Accessories...oductview.aspx
or
http://www.bintel.com.au/Accessories...oductview.aspx
The second one will add 50mm and should do the trick.