Garageband problems

Dear mac-forums users,
I recently bought a macbook pro, but when I tried to use Garageband I came upon a few problems.
I'm trying to use it to record an electric guitar.
I have an iRig connector, basically something that just connects your guitar to the computer, but when I use my external amp as an output, I can only hear the sound after I recorded.
I googled and people say I need to put on 'monitoring' in garagebox, but that doesn't work when I'm connecting an electric guitar, only with a 'physical instrument' but then I can't use the garagebox amps.

I also have another problem. When I use my external amp for effects and such, and connect that to my mac for recording (So I just want to record what my amp is producing), I'm using a 3,5 to 3,5 jack. But when I record, the internal mac microphone is still working. I can't seem to get it down. People say to just go to audio preferences but all I can select there is the internal microphone
Thanks!

Sounds like the mac isn't seeing your iRig? I'm not familiar with that particular device. When you go to Preferences->Audio/MIDI you can't select it under Audio Input?

If it's not seeing it then it makes sense that your monitoring switch isn't working....

Nope, I can't select anything else. :/
And I can only press monitoring when I'm using a 'physical instrument' track, and not when using a guitar track. Pretty weird.
And yeah, the mac isn't seeing it. But when I play something on my guitar and record it with some effects, afterwards I can hear it :S

That is odd. What do you have selected in Garageband preferences as your input device? I'm guessing Line-in?

Can only use 'Build in microphone' as well. Or I can use 'system preferences' but that wouldn't make any difference

ok... just another guess really....

but perhaps you have Monitor turned off? The monitor switch for guitar instrument is in the track header. Right beside the solo and mute switches. This is different from the "real instrument" which has the monitor on/off drop-down box in the effects browser.

Hope that helps...