Noob looking for a gamma 2.2 profile that I can use in CS3

Hello, I am quite new to color management so please excuse the basic nature of my question.

First the setup:
I have an image in jpg form taken from either a digital camera or downloaded from the web. I am interested in linearizing this image (i.e. applying a gamma .454 to the image). To do this I use Shake 4.1. I convert the image to floating point space, apply the gamma .454 to it, and then convert the image to 16 bits (because PS CS3 does not handle float images very well).

The image is now in the “correct” color space for my workflow, but it looks incorrect when I look at it in PS CS3. To compensate, I need to apply a gamma 2.2 to the image (non-destructively). So the first thing I try is to add a levels adjustment layer and setting the gamma value to 2.2. Alas, doing this leads to a significant loss of detail in the darks (it is almost as though PS CS3 were doing the adjustment layer in 8-bit space). Doing the same operation in Shake does not exhibit this issue.

So, now to my question. I would like to try using a simple gamma 2.2 curve applied via some sort of color setting to see if it shows my image in the “correct” manner. I was thinking a simple gamma 2.2 ICC profile would do it, but I do not know a) where to get one and b) whether a simple profile would even work or not (do I have to take my display devices into account?)

At any rate, if anybody has any insight, I would greatly appreciate it. And I apologize for most likely completely getting my terminology wrong. I am happy to do my own research if anyone has a good link that can get me started (I’m of at least average intelligence and should be able to learn if the material takes my inexperience into account).