Measuring resistance from 0.01 to 10k Ohms
You are attempting to measure a resistor value range that spans 6 decades or a range of 1 million to 1.  That is difficult to do using strictly linear analog techniques.

You have a couple of options.

1) Split the range into smaller segments.  Most Ohmmeters have multiple ranges, each range is a factor of 10 larger or smaller than the adjacent range.

2) Use a log amplifier to compress your 6 decade range into a more reasonable span.  Although the actual accuracy is reduced, you are able to easily see the approximate resistance value.