Problems deploying to heroku

Hi everybody,
I´m a newbee in Rails.
I have a problem, it´s with a new project connection with heroku website
(for testing and deployment).
The issue is that I want to deploy the project and when i try to use
“git push heroku master” everything seams to work ok, but at the end i
receive the following message:

Installing sqlite3 (1.3.7)
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem
native extension.
/usr/local/bin/ruby extconf.rb
checking for sqlite3.h… no
sqlite3.h is missing. Try ‘port install sqlite3 +universal’
or ‘yum install sqlite-devel’ and check your shared library
search path (the
location where your sqlite3 shared library is located).
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for
more
details. You may need configuration options.
Provided configuration options:
–with-opt-dir
–without-opt-dir
–with-opt-include
–without-opt-include=${opt-dir}/include
–with-opt-lib
–without-opt-lib=${opt-dir}/lib
–with-make-prog
–without-make-prog
–srcdir=.
–curdir
–ruby=/usr/local/bin/ruby
–with-sqlite3-dir
–without-sqlite3-dir
–with-sqlite3-include
–without-sqlite3-include=${sqlite3-dir}/include
–with-sqlite3-lib
–without-sqlite3-lib=${sqlite3-dir}/lib
–enable-local
–disable-local
Gem files will remain installed in
/tmp/build_3aqjxnpimoxm1/vendor/bundle/ruby/1.9.1/gems/sqlite3-1.3.7 for
inspection.
Results logged to
/tmp/build_3aqjxnpimoxm1/vendor/bundle/ruby/1.9.1/gems/sqlite3-1.3.7/ext/sqlite3/gem_make.out
An error occurred while installing sqlite3 (1.3.7), and Bundler
cannot continue.
Make sure that gem install sqlite3 -v '1.3.7' succeeds before
bundling.
!
! Failed to install gems via Bundler.
!
! Heroku push rejected, failed to compile Ruby/rails app
To [email protected]:afternoon-tundra-9601.git
! [remote rejected] master -> master (pre-receive hook declined)
error: failed to push some refs to
[email protected]:afternoon-tundra-9601.git’

I have been looking around in google and in the heroku help and i think
this is a database problem.
My project have the Gemfile configured this way:

group :development, :test do
gem ‘sqlite3’
end
group :production do
gem ‘pg’
end

And i try to bundle --without production but i can´t fix it.
I suppose that i have to install the PostgreSQL database, but i don´t
know how can i do that.
I have a MAC OS X 10.6 snow leopard.
Can you help me with this?
Thanks in advance.