Internet speed is slow in the rooms front of home g

Router is installed in hall and Internet is good in master bedroom and adjacent rooms 

howevere there are couple of rooms front on side and speed us very slow ,we tried wifi extender / booster still not helpful 

Can we move the router to dining without additional charges by ATT so entire home gets Internet 

or is there a better solution 

We have 1 TB fibre connection 

can we have free upgrade to resolve this ?