Best option would be to use the real bold italic version, but if you don't have it and cannot afford to buy it you can add a VERY small stroke to the text.
How do add a small stroke to the "s"?
The "s" is the character that is giving me problems.
I might have to send it out for film?
I no longer have CS2 running, but I think this should work:
Create a new Character Style and under character color clcik the stroke proxy and choose the correct color, then an appropriate weight (which will depend on the size of the text, but certainly not more than .25 pt). You can then use Find/Change to find "s" in Cochin Italic and add the character style.
But you need to understand that this in very bad typography.
As Peter says, distorting the type is rarely a good idea. That said, back in PageMaker days—before character styles—I'd occasionally beef up pseudo-smallcaps with a few percent of horizontal scaling.