@MrMazda
Absolute NoNo to put a wireless router in a basement. The router should be as high as you can get it close to where the outside connection comes in. That will dramatically change your wifi reception.
Have you ever considered a seedbox? Apart from first immediate upload the seedbox will do all the subsequent downloading at the rest using huge bandwidth. Using a seedbox you will capture a high proportion of the download volume of those leeching though I suspect you have a high ratio anyway. Even if you are only bothered as to how fast you seed to the first leechers a seedbox will get your torrent off to an immediate (immediate) start.
The seedbox will of course download almost immediately any well seeded torrent. Using a downloader from the seedbox will improve your download speeds - though unless your brother is on the computer playing games and streaming TV at the same time that shouldn't really be an issue.
Also, of course, a seedbox is the best way to secure your privacy.
I know that you must know all this. But that is an awful lot of money to be spending on equipment and additional DSL lines that you don't need.