Please don't waste money to pay a Pro. Just google your requirements and you will be fine.
If you have a wireless router, you should be able to connect wirelessly. But wireless connections are fraught with risk if it is not secured. Google "securing wireless networks". I would always recommend securing the wireless connection with WPA2/PSK.
If your router is too weak to handle wireless connections and unable to send signals through thick walls and different floors, I am afraid that you need to hard wire it or buy a powerful wireless router.