We have a script which performs ok to get few google metrics and then write them into an XML file. However, when we applied custom date values for start and end there are no differences to key metrics such as bounce/new visits.
Shouldn't take an expert more than 30 minutes to fix!
I am interested & confident for this task. Though I am new to this site, but I have previous experience in PHP, XML I have read all of your requirement. You can select me for the job.