MBA business degree? Economics Major Depaul or Northwestern Sorry question lengthy but very importnant to me?

I am deciding if I should go for my MBA immediately following my bachelor’s . . I am majoring in economics with a minor in real estate. . i just wanted to leave myself a broad base of opportunity and if so, which university? I am looking for an executive position at least eventually after exp. when I graduate for a major corporation I would like to help in the process of expanding and developing relations and growth within business through investments i dont know what this position would be called though. . I am an army vet . . . so i have worked just not using my degree if that helps at all. . . oh yeah. . i will be gettin bachelor’s from depaul but they have a dual program where i can get mba at same time. . or should i just wait and enroll in northwestern . . . because of the prestige? and networking? and reputation? these are really the only two I am considering now unless Univ. of Chicago would be a better choice. . . Oh one more thing and with this major and I believe some programs allow you to get more than one which I will more than likely do. . what would match up well with this major and minor if so? and with these majors and minors what type of positions would I most likely be eligible for? So I can look up some job descriptions. .

Detailed answers please thank you much!