Gear Upgrades

I've got "Shroud Of The Justicar" fitted and fully upgraded. I'm just a bit pissed off that the Light level is lower, and defence as well, than what is currently being sold. I doubt it's possible, but if there is a way to get it up to the new levels please let me know how? As far as I know Xur only allows you to upgrade items bought through him, and don't see any such option at NM