To colour the rows:
$objPHPExcel->getActiveSheet()->getStyle('A1000:IV2000')
->getFill()
->setFillType(PHPExcel_Style_Fill::FILL_SOLID);
$objPHPExcel->getActiveSheet()->getStyle('A1000:IV2000')
->getFill()
->getStartColor()->setARGB(PHPExcel_Style_Color::COLOR_BLUE);
To format dates:
Make sure that you’re setting your date values as an Excel serialized timestamp
$myDate = "21/12/2014 15:08:23";
$myDateValue = DateTime::createFromFormat('d/m/Y H:i:s', $myDate);
$excelTimeStamp = PHPExcel_Shared_Date::PHPToExcel($myDateValue);
$objPHPExcel->getActiveSheet()
->setCellValue('A1', $excelTimeStamp);
$objPHPExcel->getActiveSheet()
->getStyle('C9')
->getNumberFormat()
->setFormatCode(PHPExcel_Style_NumberFormat::FORMAT_DATE_DDMMYYYY);
All of this is covered in the documentation and in the examples provided with the PHPExcel package