Hey There @Fahadbin Alam You are asking some really great questions! First and foremost, does the current rent make sense to leave it? The other thing you can do is, have an open conversation with the tenants and let them know that your goal is $1,300. What is their current rent? Increase the rent every year until you are at your goal. Ultimately, if they are solid tenants who have been there for years and never skip a beat, I would not focus too strong on the rental raise. I have tenants that have been in the same property for 8 years, I raise their rent every 2 years, and they know that so there is complete transparency. Is your agent an investor themselves or giving you a general opinion? Not that it is important, more just curious.
As far as adding a bathroom with the tenants in place, this can get a bit sticky and a headache for everyone involved. Contractors trying to get into the place, tenant availability, tenants complaining that it is taking too long etc. Unless you want to relocate them temporarily and let the contractors have full access, I would'ntfocus on this. Does a bathroom raise that much rent? I have a property that is 3/2 in Akron, OH and it is about $75 more than my 3/1 located two blocks away. However, my 3/2 in Tampa is $200 more than my 3/1 in Tampa so it really does depend on the market and demand as well.
Everyone above has some great opinions, I would definitely look at the bigger picture as well :)