adding value to points

Hi all,

I have a grid of points here and i'm trying to find a way to change the number of the grid determined on how close it is to another number.

So far I have found the average of the red numbers which was around 7.3 and applied that to the whole grid .. and then now i want to be able to change the numbers depending on how close it to the red number, so it was close to 8.3, it would rise gradually move to 8.3  in the grid. and if near 5.3, it was move gradually down to 5.3 in the grid.

I have tried experimenting with moving in Z direction and trying to find a relationship between them but couldn't seem to figure it out.

Any ideas would be great.

J