DI box

[K9 Kai Niggemann]

I think you are looking for two things: a preamp and a DI box.

A DI box (the ones we use in theater) usually does nothing to the  
signal level, it mainly converts it to a symmetrical signal to avoid  
noise coming in from the dimmers (a major problem whereever there is  
light). We don't usually use them for mics, mainly for other non- 
symmetrical signals, (piezos (yes, those are mics!), keyboards,  
strings, pickups, etc).

To raise the level you should get yourself a preamp, preferably  
something with a great sounding limiter so you can push the level a  
bit and get a hot signal into your DAW.

Kai