If the Torch had another 4 years to serve on his term, and resigned, the governor could appoint a replacement to serve in his stead. At the next general election, candidates would run to fill the unexpired term of office. If the resignation took place within 30 days of the next general election, the appointee would fill the post until the next general election (which may be a year or two years... it has to be a statewide election.)
In this example, if the Torch still had 4 years to serve, and resigned today, the governor would appoint someone to serve until the end of this year, and the election would proceed as scheduled, with the new senator on the ballot, presumably. The winner of the election would serve the remaining 4 years. If he waited for two weeks before resigning, then the appointee would serve for a year or two before the position was up for election. THe winner of that election would then serve the remaining two years of the term.
The key factor here is that the Torch's term expires in January. The governor CANNOT appoint someone to serve into the next term... he doesn't have the authority. That is not an issue of NJ state law, it is a matter of the US Constitution... Senate terms cannot exceed 6 years. So there MUST be an election November 5th to determine the person who will serve the next term as NJ Senator. The only question is who the candidate will be.