Create efficient WordPress meta query

I'm working with WordPress with custom fields and trying to convert a query which was initially written for pjjtextbase (textfile database) to search a csv file for matching properties for rent/sale. The code works well but is quite inefficient. The code from the original progammer is /***** These values needed for select box *****/ $locations = ptb_listUnique($info, 'Property_Location'); $property_type = ptb_listUnique($info, 'Property_Type'); $property_buy_rent = ptb_listUnique($info, 'Buy_Rent'); //check property $query = Array(); if(!empty($_GET['location'])) { $query[] = "'Property_Location' == '".$_GET['location']."'"; } if(!empty($_GET['type'])) { $query[] = "'Property_Type' == '".$_GET['type']."'"; } if(!empty($_GET['buyrent'])) { $query[] = "'Buy_Rent' == '".$_GET['buyrent']."'"; } //check price if(empty($_GET['buyrent']) || $_GET['buyrent']=="Buy"){ if(!empty($_GET["min_val_buy"]) && is_numeric($_GET["min_val_buy"])){ $min_val_buy = $_GET["min_val_buy"]; } if(!empty($_GET["max_val_buy"]) && is_numeric($_GET["max_val_buy"])){ $max_val_buy = $_GET["max_val_buy"]; } $min_val_buy = min($_GET["min_val_buy"], $_GET["max_val_buy"]); $max_val_buy = max($_GET["min_val_buy"], $_GET["max_val_buy"]); $query[] = "'Price_Rent' >= '".$min_val_buy."'"; $query[] = "'Price_Rent' <= '".$max_val_buy."'"; }else{ if(!empty($_GET["min_val_rent"]) && is_numeric($_GET["min_val_rent"])){ $min_val = $_GET["min_val_rent"]; } if(!empty($_GET["max_val_rent"]) && is_numeric($_GET["max_val_rent"])){ $max_val = $_GET["max_val_rent"]; } $min_val_rent = min($_GET["min_val_rent"], $_GET["max_val_rent"]); $max_val_rent = max($_GET["min_val_rent"], $_GET["max_val_rent"]); $query[] = "'Price_Rent' >= '".$min_val_rent."'"; $query[] = "'Price_Rent' <= '".$max_val_rent."'"; } //check bedrooms if(!empty($_GET["room_no_min"]) && is_numeric($_GET["room_no_min"])){ $room_min_val = $_GET["room_no_min"]; } if(!empty($_GET["room_no_max"]) && is_numeric($_GET["room_no_max"])){ $room_max_val = $_GET["room_no_max"]; } $room_min_val = min($_GET["room_no_min"], $_GET["room_no_max"]); $room_max_val = max($_GET["room_no_min"], $_GET["room_no_max"]); $query[] = "'No_Bedrooms' >= '".$room_min_val."'"; $query[] = "'No_Bedrooms' <= '".$room_max_val."'"; //Now build the query to search $query = implode(' AND ', $query); I would like this to be converted into a WordPress meta array that fits into this code function propertysearch () { $location = preg_replace('/^-|-$|[^-a-zA-Z0-9]/', '', $_GET['location']); $type = preg_replace('/^-|-$|[^-a-zA-Z0-9]/', '', $_GET['type']); $buyrent = preg_replace('/^-|-$|[^-a-zA-Z0-9]/', '', $_GET['buyrent']); $min_val =preg_replace('/[^0-9]/', '', $_GET['min_val']); $room_no_min = preg_replace('/[^0-9]/', '', $_GET['room_no_min']); // This replaces characters in the input string if need be for security reasons META QUERY GOES HERE AND RESULTS = $RESULTS. if(($results == 0) || ($results == false) || ($results == NULL)) : echo '<p>Sorry, there seems to be no results for your request.</p>'; $results = NULL; return $results; else : return $results; endif; } // End of my search