Just in case no one else has posted this, Yankee batters have a HR% at home of 5.6% while it is 3.5% on the road. So the frequency is 60% higher at home (5.6/3.5 = 1.6). Yankee pitchers allow a HR% of 4.9% at home and 3.24% on the road. So that frequency is 51% higher at the new Yankee stadium (4.9/3.24 = 1.51).
That 5.6% the Yankee batters have at home would mean that each batter in your lineup would hit about 35 HRs for the whole season, assuming each batter in the lineup got 620 ABs (last year the average AL team had 5,580 ABs and that divided by 9 is 620). Then .056*620 = 34.72. Of course, you would have to do that both home and away.