Open up applescript editor and type this in:
tell application "System Events"
set textToType to "open 55x2 @ KMJT"
delay 2
repeat
delay 10
keystroke textToType
keystroke return
end repeat
end tell
hit compile then run and BAM - you have a mac autotyper.
The first delay is how long before the script starts typing, the second is how long between entering the message and in quotes you can change it to whatever you want. Once you make changes just hit compile again and run.