How to update XBMC on pre-owned device....

Hi Guys

I purchased a pre-owned Apple 1st gen jailbroken with add-ons and wish to update SportsDevil and various others..

Can anyone advise how to go about doing this? I ask because of the fact this is pre-owned, hence i don't have any existing software on my Windows PC...

Excuse my limited knowledge on the subject...

Any help much appreciated...

Happy New year to y'all...