You heard "keep someone across" the news correctly. It is not so common (evidenced in part by the response you've received here) and you are not the first to wonder about it (as you can see in this wordsmith.org forum as well as this wordreference.com forum)
However, yes, it is currently being used; here are a couple examples (with links):
"Guardian Australia will be back on deck tomorrow to keep you across all the G20 news you can handle." - from the Guardian
"We keep you across events unfolding after yesterday's plane crash in eastern Ukraine." - from BBC World Service
There are several others you can find - all from UK, Australia, or NZ and all relatively recent - simply by Googling "keep you across" (with quotation marks) and hitting "news" (as oppposed to "web"). Interestingly, there are only three pages of results, which would suggest that the history of this expression (or, to be perfectly logical, the history of the use of the expression with "you"), is relatively brief.
The meaning in the examples you can find is, in almost all cases, "keep you abreast of" something, as defined in FumbleFingers post.
However, you will find it used in a slightly different sense here, in a review of LG's G Watch R, which is touted as a...
"...highly sophisticated heart-rate monitor that helps to keep you across your daily workouts." - ITWire
But no, you won't find it in dictionaries and it would seem, given the evidence, that we are witnessing the birth of a new expression. If anyone has evidence to show that this is, in fact a revival of an older expression, I'd love to see it!
Best Answer
Although the third example appears in the Baltimore Sun, I think it's a misprint. Similarly for the fourth example from Fight News.
These should say across the street from. I believe that the articles originally used across from — that is, "...sprawls along Rote 108, across from stately mansions..." and "a hotel in South Jersey across from the Garden State Racetrack".
Across from generally means "across the street" because that's the most usual point of reference; but it could be across anything: a river, a park, you name it. The subeditor realised that and attempted to insert street and got it wrong.