How to switch between two analog outputs with a digital output?
You can do this with an analog switch like the 4066 and an inverter like the 74LS04.



As Spehro Pefhany pointed out, pullups are needed to guarantee the outputs of the 74ls93 and 74LS04 are high enough to enable the 4066. 

You may have some spare inverters (or NAND or NOR gates, which can easily be made into an inverter) already in your circuit, in which case you wouldn't need an extra 74LS04 IC.

Total cost from Digi-Key for both ICs is about 85¢ in single quantities.