Debian Configuration :: Unstable Internet Connection Squeeze - Realtek Adapter

I'm going to start using Debian as my desktop system rather than Ubuntu since I'm not really liking all the crazy eye candy and just wanted a fast and simple system. My main problem is networking, I guess I'll start off with my system specs and other information for problem solving.

My specs are:

- Intel Core i7 2600K CPU
- Gigabyte Z68X-UD3P-B3 Motherboard
- 8GB DDR3 1600Mhz RAM

I have a Realtek RTL8111/8168B Ethernet Adapter builtin to my motherboad which I am using, I could only get a basic connection, by basic I mean that it allowed me to connect to my local area network but not the internet. I then modified /etc/NetworkManager/NetworkManager.conf to change to managed=true this allowed me to use the internet, but the problem is, that it is a very unstable connection, the speed is very slow and it drops a lot! I have to carry on running /etc/init.d/network-manager restart twice to get my connection back, which lasts for about a minute.

output of lspci | grep -i eth

07:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 06)

Output of cat /var/log/dmesg | grep -i eth

[    1.414250] r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded
[    1.415080] eth0: RTL8168b/8111b at 0xffffc90000c7c000, 1c:6f:65:c5:7c:34, XID 0c900800 IRQ 31
[    9.213351] r8169: eth0: link up
[    9.213392] r8169: eth0: link up
[   13.813496] Bluetooth: BNEP (Ethernet Emulation) ver 1.3