Generally you cannot send Ripples to gateways because gateways do not want to act like Ripple wallets, you need to send USD or Bitcoin equivalent from your Ripple account.  If you contact WeExchange with date and transaction info they should be able to send your Ripples right back. But for them to do this, you first need to open in your Ripple account a Trust line with them (ask them for their Ripple Trustline address or something named like that). The trust line must be equal to or more than 40K ripples so your Ripple account can accept funds from them.