OS X v10.7.5 Update

Hi,

So I've been switching between computers for work and leisure and never had the time to update my iMac. I decided to update it to Max OS Lion 10.7.5 today but got the following error message:

"The update could not be verified. It may have been corrupted or tampered with during downloading. The update will be downloaded and checked again the next time that Software Update runs."

I turned my computer off, restarted it and tried again - same issue

Question: Should I just wait for the software update to pop up again it self or is there somewhere, where I can download the update manually? Or is there another OS update I should be updating my iMac to?

Thanks!