Automatically move multiple shapes in different directions

Question

Hi,
I posted this in the C# forum as well, but now I see there is a GDI+ forum so here goes...

I am doing a project on location tracking of assets using C#

I have bought hardware (tags and readers) to implement the system. The tags will be carried by people and they will send the tag ID to the readers who are picking them up.

In c# to determine which reader picked up the nearest signal of the tag I am sorting a list.

I am using a background worker to read the data from the readers every 3 seconds.

Now on to my problem. The system text based is working fine, however I want to represent the data visually.

So I have a picture box and I uploaded a Floor Plan map on it.
So I want to draw circles on the picture box and make them move automatically according to coordinates of the reader on the FloorPlan.
Multiple tags (circles) will have to move in different directions. However this part I can't do it.

Any hints on how to tackle this? I managed to make it work for one tag (meaning one circle - although I doubt the method used is efficient enough) but when plugging in two or more tags, multiple circles aren't being drawn.

Any help is greatly appreciated.

Thanks :)