The cost is average of landed (final) receiving cost. If you sold items before PO receive posting, the cost may not be correct. You can go avg cost field in Sku Info tab to manually fix it. Please give me a Sku example which has the wrong cost.
The currency symbol in reports can be changed in region and language settings in Windows control panel. The store attributes currency won’t work with reports.
We cannot change the extra line on the report as this may affect other reports or other clients. You can print “Raw Data” report and format yourself.