I don't think you'll be able to replace just the shower tile flooring without messing up the walls. the base goes on last, so removing your bathroom floor will mess those up, too. Sorry. Why wouldn't you upgrade the whole bathroom so it makes sense?

There is a grout paint that could lighten the grout lines of the floor - though might not hold up in the shower. Sometimes the lighter grout lines make the floor feel fresher. On a budget I would replace the countertop if the cabinet is in good shape. You might be able to get a remnant piece of quartz or granite for a reasonable price. If the cabinet is in good shape then leave it alone. I painted a bathroom cabinet and then did not like the way it showed everything and refinished it back to wood - but that was in a kids bathroom, so more prone to a little abuse. If you are keeping the light, change out knobs, faucets, and towel bars to a darker color. Pretty rug, window treatment and a few pieces of wall decor and it will be very pretty.

Take a look at this blog, it looks great.http://www.domesticimperfection.com/2013/11/how-to-refinish-outdated-tile/

Maybe that will give you some inspiration here. Also I would cut the mirror into 2 pieces (you tube has some good tutorials) and frame each with some Spanish tiles or some neat old boards and hang over each sink.

You could use some fun tiles for a backsplash

You can paint the light fixture to save it.

Paint the cabinet for sure ...

the sinks and the faucets might have to wait. They are so expensive! Well ones I like anyway...

I'd look into a company that refinishes tile. My parents did their bathroom that way and it ended up looking really nice and was quite affordable. The cabinets look pretty nice still, they have a bit of a Scandinavian look. I wouldn't do much to them.Maybe invest in the countertop being replaced. Really new lighting and paint goes a long way as well.

Here is a great design we did for one of our clients that might just give you some inspiration. Take note of the cabinet color and lighting.

A new pendant fixture..wrought iron.

Or...

A pressed tin frame for your mirror, something like this.(add some dark patina and it will easily coordinate with your new lighting fixtures.

Do a dark wash on the cabinets. Light sand and distress them a wee bit.

An easy decorative accent 'faux' wood beams above!

If you are looking beautiful bathroom lighting ideas, visit www.GalileeLighting.com

To receive our catalog by email, contact Sales@GalileeLighting.com

We deliver worldwide.

To get the most bang for your $1000 and give the BR a Mexican style here's my suggestions:
Replace light fixture with wrought iron
Replace faucets/ fixtures w/ perhaps bronze
Replace sinks with Mexican porcelain bathroom sinks (Google Mexican porcelain BR sinks)
Replace accessories (towels, tissue holder, rug, etc) with brightly colored accessories Use colors from sink for this
Find a nice succulent plant or two for bathroom
(Fake or real - jade, cactus, etc)
Replace mirror Like tin mirrors suggested in former post
Replace hardware on cabinets with wrought iron hardware
Beams suggested were also nice

I agree that I'd skip messing with the floor or shower and put the whole budget into the vanity -- darker stain and new countertop/sinks/faucets. That should be enough to give the whole place a new feel. Grout paint on the floor will be icing on the cake.

(see an example here: https://www.houzz.com/discussions/framed-the-master-bath-mirror-and-gel-stained-the-cabinets-dark-dsvw-vd~1341775?n=21 )

paint cabinets, change out fixtures, add color with art, towels etc.