Will this idea about cooling all of the components work?

[mitk0o0o0]

So I have moved my computer to my house's second floor and it's extremely hot. It's around ~33C in the room everyday due to the hot weather this month and I have noticed that when I do multiple tasks such as watching a YouTube video, using Skype and browsing the web at the same time my CPU's temperature would go ~65C and sometimes even ~70C and I get warning that Core 0 is hot. Along with my CPU, I see that my motherboard's temperature also goes up to around 70C and the whole computer case feels very hot when touched. Fortunately in idle the CPU temperature stays at ~50C as well as the motherboard.

My specs:
CPU: AMD Athlon 64 X2 5000+ Brisbane 65nm Technology
Motherboard: MSI MS-7309
OS: Windows 7 Ultimate 64-bit SP1

On the left side of my computer case I noticed that I have a hole, something like a place to attach another fan maybe? Still, I'm not sure if that's what it's about because right where the hole is located on the case, there is the CPU and its fan. Here's an image:

Notice that on the hole above there are four little holes that look like thingies to attach a fan with screws? Or that's just me.

Btw, this is the fan that I'm using for my CPU and I feel like it's not doing such a good job:

So what do you guys think about this? Is it a good idea to try and attach a cooling fan in there and most importantly, will it actually provide better cooling for my computer? For now I'm forced to take off the left cover but that increases the chances of my fans to get clogged with dust shortening their lifespan.

 

[badboyrog2]

1 = AMD Athlon 64 X2 5000+...MAX TEMP IS: 55-68'C
2 = i suggest you to buy a good cpu cooler like the cooler master hyper 212 evo
3 = clean your case and motherboard with air spray can (remove power from the pc before)
4 = keep the side panel removed

 

[mitk0o0o0]

1 = AMD Athlon 64 X2 5000+...MAX TEMP IS: 55-68'C
2 = i suggest you to buy a good cpu cooler like the cooler master hyper 212 evo
3 = clean your case and motherboard with air spray can (remove power from the pc before)
4 = keep the side panel removed

1 = So my resort is to upgrade the motherboard and CPU? I know they're pretty outdated for today's standards but I'm a bit of low in funds at the moment so I need a temporary workaround.
2 = I looked it up but I see it says "Versatile all-in-one mounting solution supporting the latest Intel LGA 2011 / 1366 / 1155 and AMD FM1 / AM3+." and I believe my CPU socket is AM2+ or something like that. Will this still work somehow?
3 = Thank you for the suggestion, I'll do that.
4 = I'm guessing this is relative to your 3rd answer. Keep the case removed and clean with air spray can regularly?

Also a question about the air spray can: This is 100% harmless for the components, right? I can spray wherever I want inside without worries, right? Then I just plug back the power coord and power it on immediatelly without waiting? I'm sorry for asking too many questions but I'm a total newbie when it comes to hardware.

 

[mitk0o0o0]

I'm back with an update to my question. I bought the Cooler Master Hyper 212 EVO and it is cooling my CPU perfectly! It's amazing! When playing games now or rendering videos, my CPU's temp barely reaches 49-50C while before it would go up to 71C.

Thank you badboyrog2 for letting me know about this.