if you're interested in AutoHotkey the best thing to do is, to try it yourself. The Help file is a good start. Browse the commands, read what they do and then think how Autohotkey can automate your task. And before you know it, you're writing your own small scripts...
Here's how I'd do it:
1.) Run MLO (command Run)
2.) Wait until MLO is closed (WinWaitClose)
2.) Upload the file via FTP (see example in command FileAppend)
1.) Download the file (URLDownloadToFile) in %temp%
2.) Check if the existing file is newer than the download file (FileGetTime... modified)
3.) Move the file from %temp% to wherever you need it or erase it from %temp% (FileMove, FileDelete)
If you insist in emailing, you can use a command line emailer http://snipurl.com/lbnr
) to send emails (Run,sendemail.exe parameters,,hide). Of course you can also start your emailer (run,mailto:firstname.lastname@example.org) and send keystrokes. Retrieving emails + extracting attachments using Autohotkey is the difficult part. I've no idea if this is possible.