With IPHost Network Monitor you can run simple snmp requests against a Cisco device in your network.
cwrBandwidth
Cisco Wireless Bandwidth
1.3.6.1.4.1.9.9.136.1.3.2.1.2
This object specifies the bandwidth to use. Given bandwidth, the actual throughput of the radio link is determined by the cwrThroughput setting.
Back to CISCO-WIRELESS-IF-MIB MIB page.
IPHost Network monitor allows you to monitor cwrBandwidth on Cisco device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Cisco wireless switches right now.