Difficult to say without the bike in front of me......but.....there are MANY guides to getting your chainlength spot on...........type 'chain length' into Google or looky here
http://www.cyclechat.net/threads/chain-length-calculator.19842/
You may find it ok to stick with the current chain length but you need to check it out to be sure.
If you have a kmc chain (or SRAM) then use the apprpriate 'quik-link' to join them. If a Shimano chain...use the supplied Shimano pin. I personally wouldn't try to use anything but the supplied joining method with a new chain.......not worth the bother or (potential) hassle.
HTH
w