How to limit bandwith of adsl broadband for the users in a home network?

I’m having a 1Mbps adsl internet connection shared by 4 users, my pc is connected via ethernet cable & the rest of them were wirelessly. If any user starts downloading or online streaming videos i can’t even browse a page. Is there any option that i can limit the bandwith usage for the each users connected to the network.

My router is aztech 4port adsl2 wireless router.