How do I import single install blog into multisite (media file location after an update of the URLs

I am bringing in a clients website into my multisite. Once done, I ran Velvet Blues Update URLs plugin to change the first part of the URL. Works well accross everything, except it does not add the /sites/sitenumber/ to the media links. How is this usually done? Is this the best plugin to use? Please advise, I really don't want to sit there updating all the media links.

Thank you in advance for your help!

Regards,

Paul