The following line in your code specifies the full path name for where the file is to be saved:
You can make the filename anything you want, just change the part to the right of the "&". If you want the filename to be taken from a cell, such as A1 on Sheet1, using the same extension as the attachment:
For example, if you have "Test" in A1 and the attachment is "Foo.xlsx" then the result will be "Test.xlsx".
I have compiled but not tested this since it requires some setup with Outlook specific to your situation.