Congratulations on your new Terp.. If you have any pictures of it we would love to see it. Sounds like by the size of it,, you probably have a female.
I really like the idea of over the tank basking areas. That way the turtle, especially as big as your is, can have the whole tank area to swim in.
You can get as creative as you want with whatever you use to make the area. You just have to ensure that your turtle can't crawl out of the tank. If she is female she will go through periods of wanting to lay eggs and do just about anything to get out..
But here is a link to Google images and you can get some ideas on what to use if you are interested.
https://www.google.com/search?q=over+ta ... gC#imgrc=_I am from Canada, Southern Ontario in fact so I know what you mean by expensive prices..lol One of the perks of now living state side..
I can't advise you on filters yet, since I still have a baby turtle in a fairly small tank. I think I am gonna get a Fluval U4 for my 40g tank.. those are under water filters but they don't' make them big enough for 100 g tanks and since you need to double or triple the size filter for the size tank.. you would need two,, and I can just imagine what they would cost up there.. Cheapest place to buy them here is online. I know how much shipping costs to send anything up there, so that really isn't a viable option for you, unless you live close to the border..
Good luck with your new turtle, the more time you spend with them the more you get back..