i will be visiting a friend in new zealand and i was hoping to see if there are any cheap flights for less than 1500-2000

i will fly out of SFO, which i hear is great for flights to australia and oceanic etc.

i will be flying around November 17th and come back around the 28th..i am semi-flexible with dates, whichever is cheaper. (it is thanksgiving time though, but thats when i have time off)

i know that United doesn't have direct flights to aukland, but they do to sydney and then i can fly from sydney to aukland via a different airline
two more questions

can i use united miles to upgrade to business class on even if im flying Air New Zealand (both star alliance)

and is ebookers.com a reliable travel website,,very cheap prices!