Which eyepiece?
Get two, Bintel aka GSO Superviews 15 and 20mm. Buy a Bintel 2x barlow 1.25" and your set.
http://www.bintel.com.au/Eyepieces-a...7/catmenu.aspx
The only problem I can see with getting a bigger scope is mounting it. The 70mm Celestron comes with a mount.
Andrews communications sell the GSO Superviews too.
Matt