Javascript Help

Hello, i am writing some javascript for a website and have stumbled across a problem.

I have this section of code:

Javascript File:

.bind('drop', function (evt) {
var id = evt.dataTransfer.getData('text'),
item = $('#' + id),
cartList = $("#cart ul"),
total = $("#total span"),
price = $('p:eq(1) span', item).text(),
prevCartItem = null,
notInCart = (function () {
var lis = $('li', cartList),
len = lis.length,
i;

PHP Page:
echo " <input type=\"radio\" name=\"credit_used\" value=\"currency1\" onclick=\"set_credit();\" >currency1<br>";
echo " <input type=\"radio\" name=\"credit_used\" value=\"currency2\" onclick=\"set_credit();\">currency2";

I want to make it so that when a user clicks on currency 1, this line:
price = $('p:eq(1) span', item).text(),
stays as it is, but if they select currency 2. the line becomes
price = $('p:eq(2) span', item).text(),

How would i go about this? i have tryed using a function and also if/else statements.
Many thanks
Ryan