How to make a real time active line chart

I have made the excel workbook [attached]
I want it to plot a two line chart of time against two updating values defined in two cells that are fed from an updating web page
I have got the data feed for the chart working using VBA so that every 5 min's a new date/time and the two values are added to the chart data feed, however the new time is not adding to the actual graph when the data updates and for some reason when i run the macro it seems to disable the "auto refresh" for the two web page's feed's

can anyone throw any light on this

cheer's

P/s often when the web page does actually manage to up date due to the web page itself the web data appears in different cells on the sheet which is why you will see that I have had to ask excel to first find the data cell i want and then place the value into another cell before the macro reads it.