Adobe Reader Touch does not support file attachments.
Adobe Reader Touch is a relatively new product. Our product management team determines which features/enhancements/updates to add based on customer feedback and the usage data collected from other mobile Adobe Reader products (e.g. Reader for iOS/Android).
While Adobe Reader for iOS/Android supports file attachments, the usage data indicates that file attachments are rarely used. So it is not clear if or when the feature will be supported in Adobe Reader Touch.
Since your operating system is Windows RT 8.1, you will not be able to install and run Adobe Reader XI (desktop app with classic UI). Because Adobe Reader XI is not compatible with Windows RT.
Microsoft Reader (the built-in PDF viewer) does not seem to support file attachments, either.
One thing that you could try is to open the PDF document with attachments in Adobe Reader XI on Windows 7, save the attachments as separate files, and transfer the files from your Windows 7 notebook to your Windows RT 8.1 notebook/tablet using a cloud storage service (e.g. SkyDrive, Dropbox, Acrobat.com, etc.)
It's not ideal. But it's one way to work around the lack of the feature. Sorry for the inconvenience.
Download foxit reader which is a free software compatible with windows 8, open your file in foxit reader and then you can see the attachment in adobe files.