Personally I would get a 6 inch inline fan for that size tent, doesn't need to be anything fancy either, they have good vivosun kits you can buy from Amazon or hydroponic shops. But if your not worried about the smell I wouldn't even bother getting the kit, I would just get the inline fan with the ducting and minus the carbon charcoal filter...
And I have a 3x4 tent and my led is 250w so I would get a bigger light if that's an option for you. Or just use the one you have until your able to get another one and you'll be golden!!! Hope this helps growmie! Happy growing! ✌️👊