Unfortunately not, you may as well bin it. There is no fix for Nag3 and probably never will be. You will have to buy one of the newer cable boxes that need an internet connection (for a work around the Nag3 issue), as well as the usual connections. Only one is currently working at present, the Kryptview A780. Starview have the Starview 7, but at present it is out of action (it is rumoured to be back working in around a week or over, but just a rumour).
Have a good scout about the Kryptview, Starview, and general Cable TV forums and do some research nick0312.