Wireless speed drops over time and doesn't get up if not reconnected on an Asus PCE-N15

Question

Possible Duplicate:
RealTek RTL8188CE WiFi adapter doesn’t connect reliably

I am using Ubuntu 12.10 64bit and I have a Asus PCE-N15 wireless card(in PCI-E slot).

The problem is that first when I connect to my WiFi network the speed is just fine, and actually my link speed never drops, it shows a solid 150mb/s+ link speed and good signal. But the download and upload speeds drop dramatically after couple minutes of use and I have to reconnect to fix this.

Network is type IEEE 802.11bgn and uses WPA2/AES encryption.

I don't have similar problems on the windows side, and the network is working fine on every other device.

iwconfig shows this:

wlan0 IEEE 802.11bgn  ESSID:"WLAN-AP"  
      Mode:Managed  Frequency:2.412 GHz  Access Point: 00:1E:AB:05:EF:31   
      Bit Rate=300 Mb/s   Tx-Power=20 dBm   
      Retry  long limit:7   RTS thr=2347 B   Fragment thr:off
      Encryption key:off
      Power Management:off
      Link Quality=61/70  Signal level=-49 dBm  
      Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
      Tx excessive retries:0  Invalid misc:2   Missed beacon:0

So the question is: Is there a way to fix this?

Thanks in advance.