How to show POI within 10km in window phone 8 map control

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C#

Windows

XAML

Silverlight

, +

I am using map control in windows phone 8. I have to show places on map within 10km nearby my current location. Till then i am able to show my current location and i have latitude & longitude.
Please tell me how to do this task.

<StackPanel>
        <TextBlock Text="Bing Map" FontSize="50" />
        <TextBlock Text="Places of Interest" FontSize="25" />
        <Controls:Map Name="Bmap" Height="400"/>        
        <StackPanel Orientation="Horizontal">
            <TextBlock Text="Latitude :" FontSize="25" />
            <TextBlock Text="" FontSize="25" Name="txt_lat" />
        </StackPanel>
        <StackPanel Orientation="Horizontal">
            <TextBlock Text="Longitude :" FontSize="25" />
            <TextBlock Text="" FontSize="25" Name="txt_long" />
        </StackPanel>                
    </StackPanel>

public static class CoordinateConverter
        {
            public static GeoCoordinate ConvertGeocoordinate(Geocoordinate geocoordinate)
            {
                return new GeoCoordinate
                    (
                    geocoordinate.Latitude,
                    geocoordinate.Longitude,
                    geocoordinate.Altitude ?? Double.NaN,
                    geocoordinate.Accuracy,
                    geocoordinate.AltitudeAccuracy ?? Double.NaN,
                    geocoordinate.Speed ?? Double.NaN,
                    geocoordinate.Heading ?? Double.NaN
                    );
            }
        }
        
        protected async override void OnNavigatedTo(NavigationEventArgs e)
        {
            var locator = new Geolocator();
            locator.DesiredAccuracyInMeters = 50;

            // MUST ENABLE THE LOCATION CAPABILITY!!!
            var position = await locator.GetGeopositionAsync();
            var myGeocoordinate = position.Coordinate;
            txt_lat.Text = position.Coordinate.Latitude.ToString();
            txt_long.Text = position.Coordinate.Longitude.ToString();
            Bmap.LandmarksEnabled = true;
            Bmap.PedestrianFeaturesEnabled = true;
            GeoCoordinate myGeoCoordinate = CoordinateConverter.ConvertGeocoordinate(myGeocoordinate);
            Bmap.Center = myGeoCoordinate;
            Bmap.ZoomLevel = 16;

// Create a small circle to mark the current location.
            Ellipse myCircle = new Ellipse();
            myCircle.Fill = new SolidColorBrush(Colors.Blue);
            myCircle.Height = 20;
            myCircle.Width = 20;
            myCircle.Opacity = 50;

            // Create a MapOverlay to contain the circle.
            MapOverlay myLocationOverlay = new MapOverlay();
            myLocationOverlay.Content = myCircle;
            myLocationOverlay.PositionOrigin = new Point(0.5, 0.5);
            myLocationOverlay.GeoCoordinate = myGeoCoordinate;

            // Create a MapLayer to contain the MapOverlay.
            MapLayer myLocationLayer = new MapLayer();
            myLocationLayer.Add(myLocationOverlay);

            // Add the MapLayer to the Map.
            Bmap.Layers.Add(myLocationLayer);

            //Use google API to show POI
            HttpClient client = new HttpClient();
            string baseUrl = "https://maps.googleapis.com/maps/api/place/search/json?location=" + position.Coordinate.Latitude + "," + position.Coordinate.Longitude + "&radius=1000&keyword=hospital&sensor=true";
            string googleResult = await client.GetStringAsync(baseUrl);
}

Someone told me to use google api to show the POI but i don't know how to use. I am beginner in WP app development. Plz help.