If you want to do it yourself then a place to consider looking is Leroy Merlin in Grand Plaza in Roquetas. They have a reasonable range of prices and styles.
To get an idea of what they stock you can look at http://www.leroymerlin.es/
It is in Spanish but bathroom is baño which is at the top of the menu on the left.
You can take things home in your car if it is big enough or you can have it delivered (at a price).
There are also many other bathroom fitting shops in El Ejido and Roquetas. One example is Newlar in El Ejido. Go straight on at the roundabout with the massive tower in El Ejido (rather than turn left for the main street) and the shop is at the end of the road on the right. They insist on fitting the shower screens themselves but you can fit your own base if you wish. The reason they insist is that they give a guarantee on the fittting. They are not cheap but have some more up market stuff compared with Leroy Merlin.
John