Modify 3d printing STL file according to my specifications

I have an STL model of a ring that I want to modify before I print it in metal. The STL file can be downloaded here: [login to view URL] What I want form the final file: The ring consists of an inner part (a normal ring shape) and some elevations/Platforms that sit on top of the ring. I will call the inner ring the "Ring part" and the platforms/Elevations the: "Elevation part" for easier understanding. The Inner Ring Part: The ring inner diameter should be 18.80mm (Ring size 59) The width of the inner Ring part should be 6mm wide The inner Ring should be 2mm thick The inner ring should be rounded on the inside and outside (Lord of the rings style Ring) The Elevations Part: The elevations should be more pronounced than on the STL file: Make the elevations protrude 1.7mm higher from the inner Ring Final dimensions: This makes the total Ring 6mm+1.7mm+1.7mm = 9.4mm wide This makes the ring 2mm+1.7mm = 3.7mm thick Please deliver as an STL file ready for 3D printing (needs to be a solid shape). You can either modify this one or rebuild it from scratch using this design. Its up to you.