In the mean time I'll take your advice and start buying beds to fill up living rooms and dining rooms. 

Purchase price: $218,000 Cash invested: $63,000 3 bed 2 bath Duplex with two 1200 sqft units.

It would make a fantastic additional bedroom to the upper unit, and would increase the overall bed/bath and square footage of the building. 

Market rents for a 3 bed are 20% higher at $850.6) Current total rent is $2800, and asking price is $314,000.

A part of the rehab is finishing the basement, which will allow us to turn this from a 2 bed/1 bath to a 3 bed/2.5 bath.

So I’m looking to buy a property around 2-3 bed 2bath what areas of improvement automatically increase the home value?

Fish town area of Philadelphia. 2 bed 2 bath.

Rents vary, but for a 2 bed condo, you can get $1050-1400 a month. 

I think the other posts have pretty much covered it from a rental perspective, but another issue is the financing.The room will not be counted as a Bed Room (BR) for financing purposes. 

Other crap like a cat in the bedroom or putting a bed in the storage room is not important.