Excel Attachment in Outlook 2010 Question

Difficult to know without more details of what was in the text file.
First thing I can suggest is increasing the attachment size limit in Outlook to allow you to send the 46MB file (see this link: https://support.microsoft.com/en-us/kb/2222370) - but only if the recipient can receive that size of file.
I think a better solution would be to upload the file to an online folder (something like Dropbox) and let the recipient download it from there - most cloud storage services allow you to share a link to one particular file or folder without sharing the whole account. (Do consider any confidentiality/privacy issues if you're doing this though!)