Add dynamic value to XML tags in Python

I am using XML renderer in Django-Rest-Framework. Which automaticaly renders the dictionary or list to XML. But in resulting XML tags i want some extra fields to be added. what should i do. What i thin is that i should change the key values of the dictionary. I don't know the way for it. TIA

Code Specification are as under:- Code in views

from django.shortcuts import render
from serializers import *
from rest_framework import viewsets
from rest_framework import status
from rest_framework.decorators import api_view
from rest_framework.response import Response
from feed.models import *
import collections

@api_view(['GET','POST'])
def feed(request):
    try:
        dub = propertyfinder.objects.all()
    except dub.DoesNotExist:
        return Response(status=status.HTTP_404_NOT_FOUND)
    bcount = {}
    if request.method == 'GET':
        data = collections.OrderedDict()
        prop = []
        for i in dub:
            data['reference_number'] = i.reference_number
            data['offering_type'] = i.offering_type
            data['property_type'] = i.property_type
            data['price_on_application'] = i.price_on_application
            prop.append(data)
        bcount['dubizzlepropertyfeed'] = prop
        return Response(bcount)

Output which i am getting

 <list>
    <property>
    <reference_number>ref001</reference_number>
    <offering_type>CR</offering_type>
    <property_type>df</property_type>
    <price_on_application>False</price_on_application>
    </property>
    </list>

Output which i want.

 <list last_update="2014-08-08 13:14:15" listing_count="834">
    <property last_update="2014-08-08 14:15:16">
    <reference_number>
    AB123
    </reference_number>
    <offering_type>
    RR
    </offering_type>
    <property_type>
    AP
    </property_type>
    <price>
    1000000
    </price>
    <service_charge>
    3000
    </service_charge>
    </property>
    </list>