If you get a new case, you will probably get a side panel, fan and a whole bunch of extra features. A much more cost efficient use of $60. Just make sure your mobo is mountable in it.
You can probably franken-puter some old fans off your current case and use them as side, additional front and top fans (new case baring). Also note that you'll probably bottleneck any current gen card on an older platform. Before upgrading your case I'd look at your mobo/cpu/ram although you may have no choice but to upgrade the case too. Doing things in bits and bobs isn't recommended.
And one thing, are you employed/have income?