Question regarding Meade DS 114?

My wife has a Meade DS 114. The Aperature is 114mm(4.5"), Focal Length 910mm f/8. The original unit came with a 2x Barlow lens and 9mm and 25mm eyepieces. Meade cannot tell me what the highest magnification of this telescope is. We bought it used and it only came with a 8mm and 9mm eyepiece. I have been told that the highest magnification on this scope is 135mm meaning that the Barlow lens would not work with the 9mm anyway. Any suggestions on what would be a decent size lens to view the night sky with? And is a barlow lens worth even buying for the scope? We are new to this and would like to learn before buying expensive scopes. Any suggestions or advice would be appreciated.