they haven't announced further plans to my knowledge, but the manga progresses beyond where GI-Final will leave off. That's actually the main reason they're doing OVA's instead of tv series though: the manga is still incomplete.

When the TV series hit the end of the completed manga, rather than pull a DBZ and fuck up their pacing, they just cut off the series. The OVA's since then have been released at logical breaking points in the manga's release schedule. If there's another story arc they animate after GI-Final, it probably won't be for another year or so from the end of it.

I think Toriyamaworld is doing manga scanslations of the current stuff... though it may be possible to find newer stuff than they have out, I dunno. If you want to sneak a read ahead (or compare the animated part to the manga so far) they should have torrents and links up at http://www.toriyamaworld.com ...