you need to ride joyce while he's hot. back to back homers and 1 for 3 with 2BB and 2R today.
anyway, your OF looks a little weak.
i'm not a fan of volq because he issues too many walks and does not go deep into games. i would take hart for volquez, even though i think hart is a high strikeout guy. he'll provide power, which i think you need.
i love matt cain, and he was the best pitcher for my giants last year. he was also ridiculous during the WS run. i am very biased. on one hand, you are full of OF, so trading away Upton doesn't look that bad. i actually think hart and upton have similar value. so hart replaces upton, leaving you with Hart, Kemp, Jones. That's not a bad OF, but that depends on how deep your league is.
i think cain is the best player. if i were in your position, i would be more willing to do the 2 for 2 instead of cain for upton.