I've had Netgear for years with very few problems, so lets not go blaming the hardware shall we!
On the matter of better filters, yes they will get you a quicker connection, but it should not effect the rate at which the connection is dropped unless you are very very far away from the exchange. If you want to up the speed of your connection (assuming you are on ADSL Max) then try one of these, they are the daddy of all filters: http://www.adslnation.com/products/xte2005.php . Saying that, it shouldnt cause your connection to drop less, it should just make it faster (ADSL Max will increase connection speed until it gets dodgy, then drops it again slightly to make it stable.)
Right, just reading through the manual so bear with me on this. Try connecting to the web interface for the router (going to http://192.168.0.1 assuming you are running it as is out of the box - username: Admin, password: password). Find the Logs section and post up what it says (obviously blank out any sensative info in there if there is any).
BTW my half day rate is currently £600, invoice in the post