The question is, are the speeds your ISP told you in kbps or KB/s? Usually ISP's will quote speeds in kbps (kilobits per second, not KiloBytes per second which is what LW uses.) If your speed is 128 kbps then you should set your connection speed to modem. This describes speed allocations:
More on LW connection speeds. Remember 8 bits =1 Byte. You can double-check your speed by doing a speed test. Choose nearest location for a speed test & only have your browser open:
http://www.t1shopper.com/tools/speedtest/