My 4 month old baby has outgrown her bassinet that is located in my bedroom. She is arms out of her sleep sack, and hits her arms on the side of the bassinet, and also moves up and down and hit her feet at the end. It is disturbing her sleep. I want to move her to her cot, but it is in her bedroom (doesn’t fit in my room). I’m not sure what to do- guidelines are to be in my room till 6 months, but she no longer fits in bassinet. What to do?

Most babies outgrow their bassinet much earlier than expected - whether that is due to their growth or they are rolling.
Most babies will also be rolling by 4-5 mths - at this stage they also need to be moved from bassinet to a cot.
Once baby is rolling, they need their arms free & the space of a cot to roll safely.  She is probably trying to roll by wriggling up & down the bassinet.
It certainly seems like it’s time for the move to her cot.
Another option, is that some parents will use a portable cot (if it fits in your bedroom) to continue room sharing till up to 6 months.

Red Nose recommends Room Sharing, for all sleeps, for the first 6 months as part of reducing the risk of Sudden Unexpected Death in Infancy (SUDI)
However, many parents are unable to room share for various reasons….. including when a cot does not it in your bedroom.

Red Nose has the following information (in part)
Parents are not expected to observe their baby constantly. 
If your baby is sleeping in a separate room check baby regularly to ensure that the baby remains on the back and the head and face remain uncovered (as baby grows beyond 5-6 months they will move around the cot and roll over; settle baby to sleep on their back but let them find the sleep position they feel most comfortable in. 
A safe cot and safe sleep environment is still necessary for babies older than 5-6 months)
The protective effect of room sharing can be partially explained by increased adult supervision and observation of the baby.
https://rednose.org.au/article/room-sharing-with-baby

It is still important that you concentrate on the other recommendations.
Even once baby is rolling, still place baby on back for sleep.
https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over