First, a shameless plug
Second, Black Student Alliances have to strike a balance between the social, the political, and the informative, as you say. I don't envy you. I was involved with both the NAACP and the BSA on my own campus. It's tough. My school didn't recognize NPHC orgs either, so we were very careful about what we did/how we included them.
Focusing on the freshman and sophomores is a great start. I'd say the average level of involvement for any campus org will be about two years anyway. The location change is also good.
If your budget is big/strong/solid, then I say go for the gusto and try to get a major speaker as the linchpin event of the year. Cornel West, Michael Eric Dyson, any of the tried and true folks that a campus will throw extra money at.
Consider a "theme" for the programming for the year and/or your administration. It will help you focus and have people on one page when it comes to understanding the point of being part of a movement. Here's an example of a theme which seems exclusive, but isn't:
"The Black Man and Black Woman in the 21st Century: Reaffirming the Mind, Body, and Spirit"
September - General body meeting/freshman orientation: have a panel discussion with seniors giving advice to freshmen
October - LGBT History Month - focus on James Baldwin, Audre Lorde, Bayard Rustin, and other black LGBT historical figures - many LGBT offices and orgs struggle to do programming of interest to students of color
November - Conduct a book discussion based on Lies My Teacher Told Me by James Loewen
(or bring him to speak) and discuss parallels between the African and Native American holocausts.
December - Chill Day - Last day of classes, barbecue on the lawn or some common area and play music
January - Black Greekdom Yesterday, Today, and Tomorrow (Get a guest speaker like Gregory Parks or Lawrence Ross or me
February - Black History Month Fliering - Post fliers every week of different heroes from Black History
March - Women's History Month events: Women's only talk/panel discussion (We called it Sister Talk at Georgetown); concurrently have a Brother to Brother discussion focused on how men can stop rape and sexual assault
April - National Stress
Out Day with Active Minds
Good luck! Hope these ideas get your juices flowing!