network manager not functioning properly with wireless

my wireless was working fine but then i did something and the network manager wont show/recognize any wireless connection. but i can connect throughmy wireless card.
$cat /etc/network/interfaces
gives the following output:

auto lo
iface lo inet loopback

iface eth1 inet dhcp
wireless-essid default

auto eth1

$iwconfig
gives the following output

lo no wireless extensions.

eth0 no wireless extensions.

eth1 IEEE 802.11g ESSID:"default"
          Mode:Managed Frequency:2.437 GHz Access Point: 00:13:46:A8:37:6C
          Bit Rate:54 Mb/s Tx-Power:15 dBm
          Retry limit:15 RTS thr:off Fragment thr:off
          Power Management:off
          Link Quality=67/100 Signal level=-66 dBm Noise level=-67 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:2020 Missed beacon:0

please help !!!