i just realized that i need a shift register and not a decoder
Well you can add a latch onto a multiplexer to give you a steady output. The 74LS259 is one such 8 bit addressable latch. I use it in this project:-
http://www.thebox.myzen.co.uk/Hardware/Transistor_Tester.html
To generate 16 outputs. The advantage over a shift register is that you just have to update the bit you want to change and it is much faster changing a bit than outputting all 16 bits or so with a shift register.