Not to worry. The same license code is valid for both 32 and 64 bit versions.
Buy, beg, or borrow a 32bit windows 7 home premium install disk. and install it.
You then have a OS that is good for 30 days.
When it comes time to activate, use the product code numbers on the bottom of your laptop.
It may activate, or it will invite you to call the microsoft automated telephone activation number.
You enter a set of about 8 4 digit numbers, and the telephone service will instruct you to enter a set of digits to allow activation.
How do I know? I had to use the same procedure with a new Lenovo G450 that was mistakenly delivered with a 64 bit OS.
I created a partition out of unused space on the supplied hard drive. It now boots directly to the 32 bit version. I think I could dual boot if I fixed up the boot loader. I plan to later replace the hard drive with a SSD, so I did not try to clean out the old 64 bit partition or the hidden recovery area.