Your temp is fine, and your CPU cooler RPM is normal for a stock AMD FX 8 cooler under full, or near full load. I'd highly recommend getting a bigger, and better, aftermarket cooler as soon as you can afford to do so, but for now, the behavior is normal and the temps are ok. I wouldn't worry about temps until they get up around 63°C. If 58°C is the MAX temp you're seeing, then you're ok for now. I'd get a new cooler soon though and I'd make sure I had every possible case fan location filled with a case fan and in the correct configuration. Top and rear fans should be exhaust, and front, side and bottom fans should be intake. At least on cases with bottom mounted power supplies. For cases with the PSU at the top, the configuration will be slightly different.
If you don't have good case airflow, it doesn't matter what CPU cooler you use. They can't cool well with hot air. Neither can the GPU cooler. They need the air in the case to be constantly exchanged several times per second with a big graphics card and high TDP CPU. A single rear exhaust alone doesn't cut it, nor does two exhausts only, a single exhaust and a single intake or intakes only. I'd recommend you populate all case fan locations first, get another CPU cooler second.
As mentioned, be sure you have the cooler fully seated as well. If you used more than a very small pea sized drop or uncooked rice grain sized amount of thermal paste, you used too much and should remove the cooler, entirely clean both surfaces with isopropyl alcohol and a lint free cloth or coffee filter, and repaste with the correct amount. If you used less than that, or none, then repaste with the proper amount.
If your cooler came with the thermal pad pre-applied, then you have the proper amount and don't need to worry about that aspect of the equation.