Any direct way to get Firmware 7.5.2 without using Airport Utility?

I have two Macs and two iPads. Recently WiFi connections have gone haywire, and it made me wonder if the firmware version 7.4.2 is at issue. Trouble is all indications on the net are that I have to use Airport Utility to download 7.5.2 firmware update, and it can't be done without using that application to do the download. Trouble my Airport 5.5.2 utility gets stuck in the middle of the download. Any idea how to fix this situation?