if the wi-fi speed sucks when you are downloading is it possible you are saturating you have already saturated your connection which is why other devices can't access anything? Mick is right though, if you are going to pay for a router you can do a lot better than the shubs. Ad you have already coughed up the dosh the best thing you can try atm is to use the two shubs in tandem. I would leave shub2 where it is currently located and put shub1 at the opposite end of the house and set it up as a wap on 2.ghz. If that doesn't work out and if you are still having problems I would put shub2 in modem mode (and yes there is a reason why modem mode exists and had to be created) and get a proper router like this
http://www.ebay.co.uk/itm/LINKSYS-CI...item1e7e9893ff which you wont have any problems with at all