Should I ever confide in sister again?

Well, I recently interviewed with a major company back East where I grew up, and was offered a position. This position would locate me 10 minutes from my family---my older sister lives 4 hours away, but now visits fairly often because she and her husband just had a baby. I called her house to talk to her husband--he's an HR manager--about how I should go about negotiating a higher offer, but got her instead and she wanted to know what I wanted. I explained that I wanted to talk to him about this matter, because I believe that I should get a higher salary---the salary offered is 24% less than what I currently earn in my job. Although the standard of living is lower, I still feel that I should at least try to negotiate a higher starting salary.

I told her not to tell my parents, as I didn't want to get their hopes up about us (my boyfriend and me) moving back East. Needless to say, she told my parents, and now she is giving me a guilt trip about the situation. She told me my father expressed sorrow, and that he was hurt because I did not tell him, which he told me today was true. She told me that the she had a right to tell my parents, especially my mother, because "...now that I am a mother, I share a special bond with mom that you don't understand, so I can talk to her about anything I want."

I want this job, but my family is very controlling. They get upset when my sister spends too much time with her in-laws when she, her husband, and their new baby visit. I want to take the job, but only on my own terms (i.e.: the offer is fair according to my skills and education). I also don't want to move back and have to spend every Sunday eating dinner at my parents' house, and hearing how much of a loser I am---despite putting myself through college, moving to the other side of the country with my boyfriend, and surviving bulimia/anorexia on my own.

I know I've posted here before, and I'm not perfect. But, this is a problem that I feel I need a better handle on, but one problem that I also feel I can solve with a little diplomacy and a little help from "friends."

Thanks.