You have several options. The first is a completely prefab shower stall.
They come in a bunch of different styles at a variety of price points.
The next option is just a prefab base and tile walls.
The last option is a full tile shower stall. That requires fabricating a base (there's a couple of ways to do that).
Generally speaking these are increasing order of complexity and cost. The current tub and walls will need to be removed back to the studs. There will be some plumbing work as well. The window, depending on how far it is off the floor, may be an issue with the prefab stalls.
Are you thinking about doing the work yourself or hiring a contractor?
Wow thank you so much for the quick response! I really want to do something similar to the last picture you posted. I'll be doing it myself with my dads help as well. My dad is very knowledgeable when it comes to building and construction work but he has never done this type of project. I've researched a lot and have a good idea on how to do it but I just wanted to get someones opinion before jumping into it.
The neat thing about tile is that there are so many kinds of tile on the market today that you're pretty much limited by only your imagination. Obviously budget is a concern for everyone but bathrooms are generally pretty small so that even high end tiles won't break the bank. I might also suggest doing some shopping in a regular tile store, where there will be larger selection that most home centers.
The biggest challenge in any shower is to keep moisture from getting into the surrounding wood structure and causing damage. Traditionally a thick piece of vinyl was laid at the bottom of the stall and that was topped by a layer of mortar (concrete) to provide a solid foundation for the tiles. The mortar had to be pitched (sloped) so that water would run towards the drain. Today companies like Schulter offer a preformed base made of a high density Styrofoam. It can easily be cut to fit the opening and then is topped with a waterproof membrane that's continued right up the walls for a water tight installation. Your Dad may want to do a little reading on those products.
Ok so I decided that i'm just going to remove all of the vinyl (which i have done already) and install tile flooring. The issue i'm having is cutting the cement backerboard perfectly. Does the cement backerboard need to fit snug around the toilet flange and against the cabinet and edges of the walls? I cant seem to cut it perfect enough to do so. Another problem is raising the toilet flange. Anyone have any experience with this or know how to do it? Any advice is greatly appreciated!
Heres some pictures of how the backerboard fits around the toilet flange...
Ideally you want the toilet flange to sit on the finished floor.
If you can't re-position the flange, then it's better that it sits slightly below the finished floor because you can use an extra thick wax ring or spacers. If it sits above the finished floor, the toilet can rock which will lead to leaks. You also want the flange to be fully supported and not floating in space because it can crack.
As for getting the backerboard under the flange, make your hole and then cut the board in half. So you have a semi-circle on each side that can slip under the flange. Typically you'll need about a 4" hole.
If you have access to the plumbing under the bathroom, I would just cut out the flange and put in a new one and the correct height. That way you have a rock solid installation that won't leak. A little more work and expense but worth it.