You may have to get a little more creative at this stage in your studying. I'd recommend reading this article on how to study for the new SAT. It was actually written before the four new SAT practice tests were released, which means the advice is geared towards students who have to work with materials from the old SAT and ACT to prepare for the test. Some of the language in the article is a little outdated (we're currently working on lots of blog updates!), so just focus on the information under the "how to study" headers for each section.
You can use passage-based questions from the old SAT to get some more practice for the new Reading section. For Writing, I'd recommend practicing with ACT English questions. ACT English questions are all passage-based, so they're very similar to what you'll see on the new SAT. For Math, you can still use Math sections from the old SAT to practice because the content hasn't changed dramatically. Just make sure you go through some sections without the use of a calculator so you're prepared for the no calculator section on the new SAT. You may also use ACT Math sections to practice because they include trigonometry questions, a topic that is new to the SAT this year. There are some older free official SAT practice tests that you can use for their Reading and Math sections here, and you can find free ACT practice tests here.