The AMD E1 1200 APU is a small, low power Dual core APU. As it only has two CPU Cores seeing 100% CPU usage is expected behaviour. If you used an AMD APU with four cores, you would see the CPU usage drop as there are two extra cores to handle the work.
As for upgrading maybe, but this is a question you would need to ask HP.
Your upgrade options if any will be dictated by what BIOS HP has written for your specific model laptop. HP should be able to tell you what the fastest processor your laptop will support and what BIOS version is required. Unfortunately laptop tech changes rapidly and there are typically very limited upgrade options.