Whilst i wholeheartedly approve of buying a decent third party router and putting the hub in modem mode, there are some issues that it won't fix, so before you rush out and spend some money on something that may not resolve your issues please could you:
set up a BQM - once set up, find the Live Graph and click "Create Sharing Link" - post that back here.
Next, browse to your hub on http://192.168.0.1 - don't log in, click Router Status - copy/paste the tables from the Upstream, Downstream and Network Log tabs back to this thread - you'll need multiple posts for this, the info wont all fit into a single one..
it will take 24 hours or so to get a useful data set from the BQM, but it's worth doing so you can make an informed decision about whether or not a new router will make a difference..