JSON Python, String to Float conversion or operand. API DATA

I wish to change JSON data to a float for calculating the price of bitcoin so I can continue with other calculations..

I have made a whole load of calculating methods and if i replace currency variable with an int or float it works fine.

Only when i get the json data from the api do i have problems..

i receive the following error with

e_b = float(btc) / float(cur)

TypeError: unsupported operand type(s) for /: 'float' and 'str'

and with simply

 e_b = btc / cur

i get

ValueError: could not convert string to float: '2,541.6300'

Here is the problem code. everything runs fine afterwards if a float or int is given..

import requests
import json

cur_price_url = "http://api.coindesk.com/v1/bpi/currentprice.json"

def bitcoin_current_price(url):
    """
        Function to return json data from API
        “Powered by CoinDesk” http://www.coindesk.com/price/
    """
    return requests.get(url).json()
btc_price = (bitcoin_current_price(cur_price_url))

def btc_cur():
    """  Displays Different Currency Rates and Information """
    print('\n\n USD: ' + str(btc_price['bpi']['USD']['rate']))
    print('\n\n EUR: ' + str(btc_price['bpi']['EUR']['rate']))
    print('\n\n GBP: ' + str(btc_price['bpi']['GBP']['rate']))
btc_cur()

bitcoin_usd = str(btc_price['bpi']['USD']['rate'])
bitcoin_eur = str(btc_price['bpi']['USD']['rate'])
bitcoin_gbp = str(btc_price['bpi']['USD']['rate'])

btc = 1
currency = 123.32
amount = 1

def cur_name():
    """ Name the Currencies """
    if currency == bitcoin_usd:
        cur_prt = "USD"
    elif currency == bitcoin_gbp:
        cur_prt = "GBP"
    else:
        cur_prt = "EUR"
    return cur_prt

def convert(cur, num):
    """simple conversion between currencies"""
    e_b = btc / cur
    print('\n' + str(1) + " " + str(cur_name()) + " is " + str(e_b) + " BTC")
    print(str(1) + " BTC" + " is " + str(cur) + ' ' + str(cur_name()) + '\n')

    e_b_con = e_b * num
    return e_b_con

print(convert(currency, amount))