it is very small budget and you have not specified it you want a house in Addis or in a small town/rural location
I would really advise you against looking for a house online like this. And 3 bedroom in Addis even in the cheaper areas will be more than your budget, maybe you can get a 2 bedroom for that price, but in an older neighbourhood and a house in not such a great condition.
It took me 2 months to find a suitable house, and I have a two bedroom place for 6000 birr (360 dollars)
my colleague down the street, who speaks fluent Amharic, got her two bedroom place for 4500 (270 dollars)
and these were very good deals
and bear in mind that you have to usually pay at least a couple of months at a time, I pay 4 months, some people pay 6, some owners ask for 12 months and if you use a broker, which is the only way to go, you have to give 1 months rent to them (if you rent for 12 months, 1/2 months rent if you rent for 6 months).
I think you may have to re-consider your budget