Question Airflow extremely restricted causing high temps and dust build-up.

[CampMaster69]

Before I start, i'll inform you guys that I'm a new member here. So feel free to move this thread to the proper forum if im in the wrong one.

So anyway, I have a pc cabinet which has no front or top fan mounts(and is sealed so I have no option of adding any)
but has only one exhaust fan on the back.
However, on the side of the case, there are 2 openings
1) One parallel to the CPU
2)One parallel to the GPU(and covers the length of it)
(both on the right panel, the left, top and front of it are completely sealed).
I currently have a stock intel cooler installed and will upgrade to a CoolerMaster Hyper T20 in a week.

My question is- since there is no front to backflow, what can I do to make my airflow horizontal for my CPU cooler to function properly?

specs:
i3-4130 [ 54 TDP ]
GTX 750ti dual fan version [ 60W tdp]
Micro ATXatx cabinet
16 GB Kingston hyperX ddr3 1600mhz cl9
Kingston 120gigs SSD
1tb 7200rpm HDD
gigabyte h81m-s1

P.S. the CPU cooler I've ordered is non-PMW.Will it cause any issues down the line I should be worried about?

https://imgur.com/a/Q248W2X

View: https://imgur.com/a/Q248W2X
[Keep in mind that the back sides of the case are closed anyway so the table itself doesn't affect any airflow]

 

[CampMaster69]

Here is a look from the inside

https://imgur.com/a/CCLxOgL

View: https://imgur.com/a/CCLxOgL

Here is the link of the cooler https://www.coolermaster.com/catalog/coolers/cpu-air-coolers/hyper-t20/