Best cooling solutions for the Corsair Carbide 200R case?

So i went ahead and bought the following yesterday:

1 x ASRock Z77 Extreme4, Z77 (dual PC3-12800U DDR3) (90- MXGKX0-A0UAYZ)

1 x Corsair Carbide Series 200R (CC-9011023-WW)

1 x ASUS VH242H, 23.6"

1 x Gigabyte Radeon HD 7950, 3GB GDDR5, DVI, HDMI, 2x Mini DisplayPort (GV-R795WF3-3GD)

1 x Cooler Master Hyper 212 Evo

1 x Intel Core i5-3570K, 4x 3.40GHz, boxed (BX80637I53570K)

1 x Seagate Barracuda 7200.14 1000GB, SATA 6Gb/s (ST1000DM003)

1 x Antec High Current Gamer M HCG-620M, 620W ATX 2.3 (0761345-06218-3)

1 x Corsair Vengeance schwarz DIMM Kit 8GB PC3-12800U CL9-9-9-24 (DDR3-1600) (CMZ8GX3M2A1600C9)

Only afterwards did I read that the case has pretty terrible cooling. The problem is that I was planning to overclock the CPU to something like 4,2 GHz and also overclock the GPU. Now I am wondering if all this overlocking will cause hear issues and if I should buy some fans. I would want to buy the fans straight away so I can put them in while building. Does anyone have any insight on this case, or maybe just want kind of fans I should use? Note that I don't have access to any US-only deals so please don't mention those.