Rails create two objects from one form - ruby-on-rails

Question

I have two models with a has_one relationship between them. The Event class which "has_one" Location. What I am trying to achieve is in the form where I create an event, I have a "Where?" field which is populated asynchronously through the Foursquare API.
Since I could not possibly migrate the whole of the Foursquare API to my own database, I want to generate a Location entry in my database the first time a location is mentioned in an event.
At the moment the result I am looking for is completed, but I think I am using to many hidden fields and a lot of javascript assignments. Is there a better practice than the one I am using to achieve the same result?
new.html.erb
<%= form_for :event, :url=> new_event_path, :method => :get, :remote => :true, :html => {:class => 'form-horizontal'} do |f| %>
<%= fields_for :location do |f1|%>
<%= f1.hidden_field :lat, :id=> 'foursquare-latitude' %>
<%= f1.hidden_field :lng, :id => 'foursquare-longitude' %>
<%= f1.hidden_field :foursquare_id, :id =>'foursquare-id' %>
<%= f1.hidden_field :name, :id =>'location-name-field' %>
<% end %>
<!-- TODO Encapsulate in location model -->
<%= f.hidden_field :latitude, :id=>'latitude-field' %>
<%= f.hidden_field :longitude, :id=>'longitude-field' %>
<div class="control-group">
<%= f.label :title , :class => "control-label" %>
<div class="controls">
<%= f.text_field :title %>
</div>
</div>
<div class="control-group">
<label class="control-label" for="location">Where?</label>
<div class="controls">
<input type="text" id="location" data-provide="typeahead">
<br/>
<img src="../img/fsq.png" alt="Powered By Foursquare" width="240px" />
</div>
</div>
<div class="control-group">
<%= f.label :body, :class => "control-label" %>
<div class="controls">
<%= f.text_area :body, :rows => 6 %>
</div>
</div>
<div class="control-group">
<div class="controls">
<%= f.submit %>
</div>
</div>
<% end %>
events controller
def new
#location = Location.new(params[:location])
if #location.save
#event = Event.new(params[:event])
#event.author = current_user
#event.location_id = #location.id
respond_to do |format|
if #event.save
format.js {render :action => "new"}
else
format.js {render :action => "new"}
end
end
end
end