http://www.pacsun.com unfortunately does not ship internationally but hopefully your friends/family back in states can help you out!
http://www.zumiez.com ships internationally but they are currently having a free shipping promotion for US addresses. If you have any friends or family in the states right now, maybe they can bring it to Singapore for you!
http://www.zalora.sg is based in Singapore. For orders under $40SGD, it’s $3.90SGD flat rate and free shipping for orders above $40SGD! You can also pay cash upon delivery.