Charm in the Final Hour

A trader holds a call struck at $K = \$25$ on a stock currently trading at $S_0 = \$5$; the call is quoted at $C_0 = \$0.3$ and expires in one hour. Its charm (the decay rate of delta with respect to time) is $-0.04$. If the stock slips by $\$0.5$ over the coming minute, roughly where should the call be marked?