How do I boost my wireless signal to the top floor of the house?

Wireless router is on the bottom floor, North side of the house. House has three tall storeys including the ground floor. Problem is on the third floor, South side of the house. Wireless signal is very patchy, almost non-existent.How do I boost my wireless signal to the top floor of the house?
1.you should position your router in a central position,

2.you can move the router off the floor and any metal objects,

3.you'd better replace your router's antenna

4.add a wireless repeater:

a wireless repeater extends your wireless signal range without using wire

5.it's good to update your wireless driver

have a good day connecting to internetHow do I boost my wireless signal to the top floor of the house?
You can buy new router which has more frequency rate or you can buy wireless extender.
better router