MikroTik RB951Ui-2HnD WiFi and 3G USB modem

Hello, I have RB951Ui-2HnD and 3G usb modem and want to know whether WiFi interfere with 3G signal?

If yes, what is the best option - to use usb extender or external antenna for the modem?

See my setup here on this link. in dutch but see the printscreens a made

I had 10 Mbit throughput

http://www.wirelessinfo.be/index.php/mikrotik/pages/3g