applescript or osascript to open and save excel files within matlab

I am using Matlab R2012a on a mac OS.

I am downloading data that is updated regularly from the internet that comes in the form of a .xls file. Using xlsread on this file causes problems, but if I save the file as a .xlsx, no problems arise.

I need to automate the conversion of the .xls to .xlsx within the code so that I can access the updated data set in real-time. I think that I can use applescript or osascript to achieve this but I am a little over my head in terms of figuring out how I implement this in Matlab.

Does anyone have any insight into how I might go about this?

Thanks,

Simon