Improve and debug data grabbing script

Avg Bid (USD)
Project Budget (USD)
$30 - $250

Project Description:
I have PHP script that takes data from such page like this and puts data to mysql db.

I need improvement:
to set configurable lines to take per one time, next time when script activated it has to continue take lines from where it stopped;

I need debug:
it doesnt start to take lines from some similar pages, need debug and fix.

For interested freelancers ill show the code of the script.

Skills required:
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