Here is the code you need to use. Just change the red to the things requested.
<form target="paypal" action="https://www.paypal.com/cgi-bin/webscr" method="post">
<input type="image" src="https://www.paypal.com/en_US/i/btn/btn_cart_SM.gif" border="0" name="submit" alt="PayPal - The safer, easier way to pay online!">
<input type="hidden" name="add" value="1">
<input type="hidden" name="cmd" value="_cart">
<input type="hidden" name="business" value="
Insert Your Paypal E-mail">
<input type="hidden" name="item_name" value="
Insert Product Name">
<input type="hidden" name="amount" value="
Insert $ Amount">
<input type="hidden" name="no_shipping" value="2">
<input type="hidden" name="currency_code" value="USD">
<input type="hidden" name="lc" value="US">
<input type="hidden" name="bn" value="PP-ShopCartBF">
</form>