liv | Graphic design help? (Reply)

OK, so this is in fact wedding-related, but I need the benefit of your wisdom in an area that isn't really specific to weddings. Namely, we're trying to get invitations custom-printed. We have a scan of a beautiful line drawing by

hatam_soferet, and we're trying to combine it with text saying "Jack and Liv request the pleasure of your company etc". The printing-company have asked for a 1:1 scale PDF; however, I'm completely unable to create such a file without everything ending up horribly pixellated. Do you have any good suggestions for how to do this?

Things I have tried:

Combining text and image in Open Office's equivalent of Powerpoint, Impress, then export to PDF. This leads to really awful resolution.
Combining text and image in Photoshop (albeit and old version, I'm only up to PS5), then saving as PDF. This leads to a PDF with pretty bad resolution, which is also much bigger, in physical dimensions, than the original 1:1 scale image I saved.
Saving the Photoshop file as .png (with the intention to ask the printers if they can cope with other graphic formats). At low res this gives a poor quality image, at high res this gives a (physically, I don't care about file-size) huge image.

Things I could try - which do you think would be most likely to work?:

Fiddle with the image dimensions and resolution until I get something that magically comes out 1:1 when I change the file format.
Ask the artist to rescan the line drawing into a format more suited to line drawings than jpg.
Send the text and image to a friend who has more suitable software for this task. Any volunteers?
Download some software that's better at making PDFs out of line-art than what I have. I'm willing to pay a few tens of pounds for this because it could be useful for work as well as personal stuff; I'm not willing to buy anything on the scale of Adobe Illustrator!

Umm, anything I haven't thought of? I have some experience of messing around with graphics because there are similar issues when you're trying to prepare figures for publication in journals, but I'm stumped by this one.

Also, does anyone know a better font than Italianno? I'm looking for something calligraphy-ish, but a reasonably legible Italic style rather than a very swirly copperplate or anything very loopy or elaborate. Italianno is about right aesthetically but I don't really like its numbers, and there are a few minor infelicities in the way the letters combine.