I have a sneaking suspicion that "real time toolbox" is a reference to the produce formally known as "Real Time Workshop", and currently known as "<http://www.mathworks.com/products/simulink-coder/index.html Simulink Coder>". This product requires MATLAB, Simulink, and MATLAB Coder before it will run. It is released for OS-X (I didn't think it was.)
If that is the package that is being referred to, then possibly you do not require the package at all, in the sense that the requirement might been specified erroneously, or in the sense that you might possibly be able to get around needing it by writing your own C code. The package is not necessary in order to do "real time" operations in OS-X, and the package is not necessary in order to communicate with a pre-programmed computer that is running a "real time operating system". The package is for writing code in MATLAB or Simulink and generating equivalent C code that is to be compiled and executed on a real-time operating system. This package might make sense in context if your program is creating different EEG filters or the like -- if it is reprogramming the very way that the EEG system does its data collection or analysis.
There is another possibility, which is that the package referred to might be "<http://www.mathworks.com/products/rtwt/ Real-time Windows Target>". That package is for having an MS Windows computer emulate a real-time operating system so that you can run real-time or hardware-in-the-loop simulations. It seems unlikely that such a package would be required for the purposes you describe, but people do get confused about what the packages are for.
There are two packages that seem more plausible to me than either of the above: it would be reasonable if your system needed to have either the Data Acquisition Toolbox (for handling analog/digital convertors) or the Instrument Control Toolbox (which can be similar in intent but is useful for communicating with Scopes, Signal Generators, programmable A/D and D/A convertors, and other kinds of commanded remote instruments.) Sometimes these packages can be worked around and sometimes the work-arounds would cost far more than it would be worth.
