One proposal floated by Turnpike Authority board members today at their monthly meeting would increase the charge for passenger cars on the eastern portion of the roadway by $1, increasing the cost at toll booths at Allston-Brighton and Weston from $1.25 to $2.25. Another alternative would raise the fare for tunnels by $5, from $3.50 to $8.50. The four-member board also seemed to agree that tolls will have to be reinstated for passenger cars on the western turnpike for Exits 1 through 6.