According to IFI's published data,
here (.pdf), the typical draw of the RC is between .75 and 1.5 amps, likely very dependent on the radio's draw. So far as I know servos are still powered by the back up battery. Maximum voltage is 15, and minimum is listed as 7, although I've noticed that radio performance degrades quickly as voltage drops below 12. If you operate with a tether then the OI will also be powered by the RC.
The power supply you've got should be capable of running the RC easily. The RC will draw exactly the same current for a given voltage regardless of the supply. However, as others have noted, switching power supplies are not always the cleanest sources, and the high current rating of this supply suggests that it's not intended to power sensitive micro electronics like that in the RC. If possible it would be nice if you could use a 'scope to look at the output and ensure that it is 'clean' and the supply is calibrated. Failing that a multimeter will at least ensure that the voltage it creates is in fact what it says it should be.
Most teams power the RC using one of the supplied batteries while testing. I would recommend doing the same, and using a fast acting fuse or breaker with a 3 to 5 amp rating, regardless of the supply, to safe guard both the RC and the supply. A charged battery should be capable of running the RC for several hours.
-Andy A.