We don't have any specifics, its all vague at the moment, and its worth noting that everything will always be obsolete. You can only hope for less-obsolete, and the 930/1520 models are as good as it gets right now.
The next higher model may not come for a while (920 released 2012) but rumors indicate a new high end in the pipeline.
How soon? Who knows, if you can wait, I don't see why not, but don't put off a purchase waiting indefinitely for the sake of a chance at something better, that will always happen.
If I were to speculate, other than the McLaren high-end rumors, I would assume Nokia would continue updating the mid range and low end with models like the 730.