Yes all you need to control Bitcoin adress is a private key . If you are have a private key and you need to send the bitcoins somewhere then you should import the private keys to a wallet like Blockchain.info however it's not recommended to keep the BTC's there for a long time . always use Desktop wallet instead of online .

if you want to check your bitcoin balance you should only give your bitcoin address and NOT private key. you can do that in any online block explorer:
www.blockchain.info http://btc.blockr.io

bitcoin addresses start with 1 or 3 and private keys usually start with 5

if you import your private keys in any wallet you can spend those coins.

p.s. move this to Beginners and help section
p.p.s. how are you a newbie with a member account?

To read your balance or to receive bitcoin the address is enough.
To send bitcoin (which means for most of us actual control) then you need your private key.

One easy way to use this is to create a file with content = a line like:

xxxxxxx 2015-07-14T14:25:22Z

where xxxxxx is your private key and import it into Multibit.

Edit: file name is whatever.key

Look at how you guys are all helping a scammer.
Did anybody look at his trust?

maybe a hardware wallet is more secure for you:

https://bitcointalk.org/index.php?topic=899253.0

You need a wallet too, of course, and internet to propagate your transaction.