$70 USD for two adults is really only about 54 Euro. Most Galway City B&B's and budget hotels within walking distance to the train station charge about 50 Euro per night for a single room, and 60-75 Euro for a double.
Also, I don't know what days in July you are traveling, but for 2 weeks in July there is the Galway Arts Festival and then towards late July the Galway Races take place. Hotels and B&Bs are typically more money during this time.
You may want to consider staying further out in Salthill and using a taxi or bus to get to/from the Galway train station. Otherwise, if you must stay in Galway City you could: 1) email some of the B&Bs along College Road and see if they are able to work with you on the rate; 2) email the Galway Tourist Information office and see if they have a list of B&Bs in your price range; 3) try a name your own price on Priceline for a hotel and keep your fingers crossed it's conveniently located; or 4) try to book a double in a hostel (I'd avoid this if you are there during the Galway Races as it's party central for a lot of Irish so you'll likely get little sleep in a hostel during that time).