While you do need a mac to publish your book to the iBookstore, you don't need one to update much of your metadata, including title, subtitle, description, categories and pricing.
Step 1 - login to your iTunes Connect account
Step 2 - Click on My Books
Step 3 - Click on your book Cover
Step 4 - Click on the 'edit' button next to the title 'Metadata'
Note: if you want to update pricing, you'll need to click on the Rights and Pricing button
Step 5 - Update the information accordingly on this screen
Note: if you want to change your author name as listed, you will need to click on the 'Contact Us' link at the bottom of your screen (after you login):
And then follow the prompts: