Suzanne, the question asked by @MikeWayzovski is an important one and you should deal with that first. No point starting with a new computer that has an inadequate GPU. Determine what graphics card/adaptor is included with the computer and make sure it meets, or better, exceeds the requirements.
The color you are seeing might be just due to the selected template.
As the files you are asking about, install extensions and plugins fresh from their sources. The two major sources for extensions and plugins are the Extension Warehouse and Sketchucation. If you used the Extension Warehouse tool in SketchUp to install extensions on your previous computer, you can install those same extensions automatically after signing into the EW in SketchUp on your new machine. If you had installed the Sketchucation Plugin Store extension and used it to install extensions and plugins from Sketchucation, it also has the same ability to automatically install fresh copies of your bundle of extensions.
As for custom materials, you’ll need to find the folder(s) on the old computer and copy them to the new one.
If you are giving up on the old computer, make sure you remove your SketchUp license before uninstalling the program. Otherwise you’ll leave your license tied up on the old machine.