If you usually use Matlab for analysis the files, you might want to consider using Simulink and then just generate the code of the filter. Especially if this is something you run in real time (ie inputting audio and processing it on the fly).
Another approach is using the coefficients as was suggested above.Once you have those you can use the following formula:
output[i] = A * in + A * in + A * in - B * out - B * out;
Where A/B are you coefficients, in[0,1,2] are 3 points of you original file and out [0,1,2] is the filtered one. Of-course for the first few points there are no values of out[0,1] and you should erase them after filtration.
By running this formula and shifting both in and out at each point you will result in your filtered signal.
See this thread for further explanation