Solidium script for a smart contract for a brokerage wallet exchanging eth back for a custom token

RPBroker.sol

pragma solidity ^0.4.8;
contract Token {
    event Transfer(address indexed from, address indexed to, uint256 value);
    function transfer(address _to, uint256 _value);
    function balanceOf(address) returns (uint256);
}

contract owned {
    address public owner;

    function owned() {
        owner = msg.sender;
    }

    modifier onlyOwner {
        if (msg.sender != owner) throw;
        _;
    }

    function transferOwnership(address newOwner) onlyOwner {
        owner = newOwner;
    }
}

contract TokenSale is owned {

    address public asset;
    uint256 public price;

    function TokenSale()

    {
        asset = 0x8eA88DDefA3B470B51c108475ed2073845a3944C; // RP contract
        price = 0.000000001 ether; // equals Roughly $1 USD eth for 1,000 RP @ 100$ eth
    }

    function transfer_token(address _token, address _to, uint256 _value)
    onlyOwner()
    {
        Token(_token).transfer(_to,_value);
    }

    function transfer_eth(address _to, uint256 _value)
    onlyOwner()
    {
        if(this.balance >= _value) {
                    _to.transfer(_value);
                }
    }

    function () payable {

        uint order   = msg.value / price;

        if(order == 0) throw;
        
        uint256 balance = Token(asset).balanceOf(address(this));

        if(balance == 0) throw;

        if(order > balance )
        {
            order = balance;
            uint256 change = msg.value - order * price;
            msg.sender.transfer(change);
        }

        Token(asset).transfer(msg.sender,order);
        }
}