;)
Ruh-Roh, someone's in trouble! You are sweet to try to find a replacement for Mother's Day, but it may be like trying to find a needle in a haystack, to match the existing shade.

That looks like frosted glass. Google 'vintage lamp globes' or 'vintage frosted glass globes'. Good luck--sorry about the size of pics.

Here is a link that might be useful: antiquelampsupply

Uh oh! The decoration on the lamp shade and the broken center globe matches. You'll need both pieces or an exact match of the globe to restore this lamp to its former glory.

You may find it of interest to poke around in the site below. It has may repair parts for vintage to late model lamps. However, I did not find a decorative globe to fit your lamp. You might be able to adapt a globe shade, the ones with openings at top and bottom.

Here is a link that might be useful:

If you're desperate and financial enough, these people may be able to custom paint a shade for you:

Here is a link that might be useful: Custom Glass Shade supplier