Spree Mutli Currency Converter

I am using spree for my shopping cart and i want multi currency support so i use below gem in my gemfile

gem "spree_multi_currency", :git => "git://github.com/pronix/spree-multi-currency.git"

and than did bundle install

rake spree_multi_currency:install:migrations
rake db:migrate

And then load currency using below code

rake spree_multi_currency:currency:iso4217

Now I want to Load rates from google and make USD as default currency for that i type it on terminal

rake spree_multi_currency:rates:google[USD]

but it gives error like

Loads currency data from Google using #<Spree::Currency:0xb967020>

http://www.google.com/ig/calculator?hl=en&q=1INR%3D%3FEUR rake aborted! 757: unexpected token at /home/tps/.rvm/gems/ruby-2.0.0-p247/gems/json-1.8.1/lib/json/common.rb:155:in parse' /home/tps/.rvm/gems/ruby-2.0.0-p247/gems/json-1.8.1/lib/json/common.rb:155:inparse' /home/tps/.rvm/gems/ruby-2.0.0-p247/bundler/gems/spree-multi-currency-0abaa72ab8ed/lib/tasks/spree_multi_currency.rake:126:in block (4 levels) in <top (required)>' /home/tps/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-4.0.2/lib/active_record/relation/delegation.rb:13:ineach' /home/tps/.rvm/gems/ruby-2.0.0-p247/gems/activerecord-4.0.2/lib/active_record/relation/delegation.rb:13:in each' /home/tps/.rvm/gems/ruby-2.0.0-p247/bundler/gems/spree-multi-currency-0abaa72ab8ed/lib/tasks/spree_multi_currency.rake:122:inblock (3 levels) in ' /home/tps/.rvm/gems/ruby-2.0.0-p247/bin/ruby_executable_hooks:15:in eval' /home/tps/.rvm/gems/ruby-2.0.0-p247/bin/ruby_executable_hooks:15:in' Tasks: TOP => spree_multi_currency:rates:google (See full trace by running task with --trace)

I want multi currency support for my shopping cart please help.

Thanks in advance

Add currency rate from admin side. for example USD basic currency than in converter you select your currency(INR), set nominal rate means 1 usd = 63 INR than as nominal you take 63 as nominal and 1 as value.