Wireless randomly dropping connection

Having some serious issues here and it's really beginning to annoy me. I'm hoping that I won't have to blow money on a new adapter so soon.
So, we have satellite internet which feeds to a router downstairs, we have a wireless network set up with this router that I and my family connect to. I have serious connection issues, and I'm the only one to have them. I will get severely reduced speeds sometimes, dropping down to 40KB/s downloads whilst my brother in the room next to me hits 2MB/s. I get several DCs a day and sometimes I just repeatedly DC for around an hour. My brother uses the exact same wireless adapter as me.
Router: TP-Link TL-WR1043ND Ultimate Wireless N Gigabit Router
Wireless adapter: TP-Link 300Mbit-WLAN-USB-HIGH-GAIN-Adapter with 2 Antenna
Operating System: Windows 7 64bit

Others may use the internet whilst i cannot.
Signal strength is 4bars.
Thank you in advance.