Yeah, I don't think your computer is powerful enough to run Bitcoin Core and sync in a reasonable amount of time.
I recommend that you use a different, lightweight wallet such as Electrum. You will need to export the private key for your address and sweep the Bitcoin into an Electrum wallet.
First, you will probably want to do this with your computer offline so that you aren't constantly downloading blocks. Next, start up Bitcoin Core. Go the Help > Debug Window and click on the Console tab. In the box at the bottom, type
where <address> is the address that you received Bitcoin at. Hit enter. You should see a string in black appear with begins with a '5','K', or 'L'. This is your private key. DO NOT SHARE THIS WITH ANYONE. ANYONE WHO HAS IT CAN SPEND YOUR BITCOIN. Copy that string. Now stop Bitcoin Core and go back online.
Next go to Electrum. Make a new Electrum wallet and follow the instructions for making a new wallet. Once the wallet is up, go to Wallet > Private Keys > Sweep and enter your private key into the text box. Click Sweep and all of your funds will go into Electrum now. You can and should use Electrum now as your wallet.
Now to free up the space on your computer. You can uninstall Bitcoin Core. Then go to
%appdata%/Bitcoin. Find the wallet.dat file . It contains the private key you just exported. You should hold onto that just in case. Put it in a safe location. Once you have secured the wallet.dat, you can just delete that entire folder and it will delete the blockchain and free up space.