How do I lengthen/expand an Excel chart to make it physically longer in size?

I have a line chart in Excel that has 35 dates (Apr '09, Sep '10 etc) along the X axis and a Y axis that represents the numbers recorded on those dates (between 0 and 15). The chart represents what I need it to, but the dates are all scrunched together at the bottom and it's hard to read them or tell what the corresponding date is for each of the points along the line. Is there any way to make the chart longer so that everything isn't so squashed together? The chart looks to be about 8 inches (height) by 10 inches (width) and I'd like to make it in a panoramic style at around 8 inches in height by 30 or 40 inches in width. Can this be done using Excel (or any other program)? Thanks.