Let and rent Spain

Google Maps is a fantastic tool provided by Google and while it is improving all the time, it is limited because it takes it's information from (postal) street addresses.
Your address may not be recognised by Google.

If this is the case, from your admin panel>

Just enter your city twice
Once under "City if not listed" and also under "Street Address"
Save your changes by clicking "Next" and sign out from your admin panel.
Preview the map on your advert and zoom into where your property is located and make a note of the nearest street.
You can then log back into your admin panel and enter this street name into the fields as above (twice)
You can then add a note to your description indicating that your property is, for example: "The property is just 50 meters from the point shown on the map provided by Google"
Now with the facility to add the Latitude/Longitude of the location to accurately plot on Google maps, you can either use a GPS or Sat Nav to get this information or find your property on Google earth and note the Lat/Long. The information must be entered in Decimal degree format.
If you need to convert from Degrees, Minutes and Seconds you can find a good converter http://www.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html