sleepydoodles:
If you are applying R1, there is really not enough time to do anything meaningful without it looking like blatant resume padding.
If it makes you feel any better, there's no real way to boost your quantitative credentials other than through the traditional components of the application: GPA (including relevant coursework), GMAT/GRE Quant section (your score is fine!), germane work experience in something technical, and letters of recommendation speaking to your quant/technical capabilities. Extra courses are kind of meaningless and will not move the needle.
Your best bet in your application is to focus on your strengths and rely on the Q49 on your GMAT to show your ability to handle the technical rigors of the MBA program. If you are accepted and the school deems you need more 'quant' training, they'll have you complete pre-math camps or training programs through their curriculum.
Let us know if we can of additional help as you gear up for R1.
https://admissionado.com/free-consultation/Good luck,
Admissionado